CodeGuru Forums - C++ (Non Visual C++ Issues) http://forums.codeguru.com/ Ask or answer C and C++ questions not related to Visual C++. This includes Console programming, Linux programming, or general ANSI C++. en Tue, 21 May 2013 04:20:33 GMT vBulletin 60 http://forums.codeguru.com/images/misc/rss.png CodeGuru Forums - C++ (Non Visual C++ Issues) http://forums.codeguru.com/ Looking for chars in string. http://forums.codeguru.com/showthread.php?537143-Looking-for-chars-in-string.&goto=newpost Mon, 20 May 2013 15:10:39 GMT Hi gurus.

I'm looking for a algorithm to search portions of string that have the same caracter. The only possible values are: a,n and g

Char index: 0 1 2 3 4 5 6 7 8 9 RESULT
------------------------------------------
Example 1: a g g g a a 0,4
Example 2: g g g a n n a 0,3
Example 3: a g g g g g g a 0,7
Example 4: g g g g g g g 0,6
Example 5: g g a a g a a a g 0,2,3,5,7,8


Thanks in advance, I'm collapsed :o

Best regards ]]> C++ (Non Visual C++ Issues) juanpast http://forums.codeguru.com/showthread.php?537143-Looking-for-chars-in-string. Problem in Algorithm Recursive? http://forums.codeguru.com/showthread.php?537131-Problem-in-Algorithm-Recursive&goto=newpost Sun, 19 May 2013 23:35:44 GMT #include #include #include #include #include #include using namespace std; int n , dp [1000][1000], x, y, xx, yy; bool mark [1000][1000]; struct Punto { int x; int y; }; Punto inicio, fin , aux; queue < Punto > lista; int direcciones[3][2] = { {0,1}, {1,0}, {1,1} }; void BFS() { lista.push(inicio); dp[ inicio.x ][ inicio.y ] = 1; while( !lista.empty() ) { aux = lista.front(); lista.pop(); x = aux.x; y = aux.y; for(int i=0 ; i<3 ; i++) { xx = direcciones[i][0]+x; yy = direcciones[i][1]+y; if( xx>0 && xx <= n && yy > 0 && yy <= n ) { dp[xx][yy] += dp[x][y]; if(!mark[xx][yy]) { mark[xx][yy] = true; aux.x = xx; aux.y = yy; lista.push( aux ); } } } } } int main() { cin>>n; cin>>x>>y; inicio.x = x; inicio.y = y; cin>>x>>y; fin.x = x; fin.y = y; BFS(); cout<< dp[fin.x][fin.y] < #include #include #include #include #include #include #include #include #include #include using namespace std; int n , dp [1000][1000], x, y, xx, yy; bool mark [1000][1000]; struct Punto { int x; int y; }; Punto inicio, fin , aux; queue < Punto > lista; int direcciones[3][2] = { {0,1}, {1,0}, {1,1} }; void BFS(Punto aux){ x=aux.x; y=aux.y; for(int i=0;i<3;i++){ xx=direcciones[i][0]+x; yy=direcciones[i][1]+y; if( xx>0 && xx <= n && yy > 0 && yy <= n ) { dp[xx][yy] += dp[x][y]; if(!mark[xx][yy]) { mark[xx][yy] = true; aux.x = xx; aux.y = yy; BFS( aux ); } } } } int main() { cin>>n; cin>>x>>y; inicio.x = x; inicio.y = y; cin>>x>>y; fin.x = x; fin.y = y; dp[ inicio.x ][ inicio.y ] = 1; BFS(inicio); cout<< dp[fin.x][fin.y] < Hello friends, I have a problem to implement a recursive version of an algorithm that I made, I get different values, I hope you can help me, here are the code so Iterative (OK) and Recursive code form that is not OK.

The data sets do not give equal:

The algorithm is given two source and target positions on a board, find the number of paths between them...

Input Example: 5
2 3
4 4
Output Example:

5



I hope its not help that I'm wrong!!!

Iterative Algorithm ( OK )
Code:
#include <iostream>
#include <stdio.h>
#include <cmath>
#include <algorithm>
#include <string.h>
#include <vector>
#include <queue>

using namespace std;
int n , dp [1000][1000], x, y, xx, yy;
bool mark [1000][1000];

struct Punto
{
    int x;
    int y;
};

Punto inicio, fin , aux;
queue < Punto > lista;
int direcciones[3][2] = { {0,1}, {1,0}, {1,1} };

void BFS()
{
    lista.push(inicio);
    dp[ inicio.x ][ inicio.y ] = 1;
    while( !lista.empty() )
    {
        aux = lista.front();
        lista.pop();
        x = aux.x;
        y = aux.y;
        for(int i=0 ; i<3 ; i++)
        {
            xx = direcciones[i][0]+x;
            yy = direcciones[i][1]+y;
            if( xx>0 && xx <= n && yy > 0 && yy <= n )
            {
                dp[xx][yy] += dp[x][y];
                if(!mark[xx][yy])
                {
                    mark[xx][yy] = true;
                    aux.x = xx;
                    aux.y = yy;
                    lista.push( aux );
                }
            }
        }
    }
}

int main()
{   
    cin>>n;
    cin>>x>>y;
    inicio.x = x;
    inicio.y = y;
    cin>>x>>y;
    fin.x = x;
    fin.y = y;
    BFS();
    cout<< dp[fin.x][fin.y] <<endl;
    system("pause");
    return 0;
}
Recursive Algorithm ( not OK )
Code:
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <vector>
#include <cmath>
#include <queue>
#include <map>
#include <iostream>
#include <string>
#include <stack>
using namespace std;
int n , dp [1000][1000], x, y, xx, yy;
bool mark [1000][1000];

struct Punto
{
    int x;
    int y;
};

Punto inicio, fin , aux;
queue < Punto > lista;
int direcciones[3][2] = { {0,1}, {1,0}, {1,1} };

void BFS(Punto aux){
        x=aux.x;
        y=aux.y;
        for(int i=0;i<3;i++){
                xx=direcciones[i][0]+x;
                yy=direcciones[i][1]+y;
                if( xx>0 && xx <= n && yy > 0 && yy <= n )
                {
                        dp[xx][yy] += dp[x][y];
                        if(!mark[xx][yy])
                        {
                                mark[xx][yy] = true;
                                aux.x = xx;
                                aux.y = yy;
                                BFS( aux );
                        }
                }
        }
}

int main()
{
    cin>>n;
    cin>>x>>y;
    inicio.x = x;
    inicio.y = y;
    cin>>x>>y;
    fin.x = x;
    fin.y = y;
 
    dp[ inicio.x ][ inicio.y ] = 1;
    BFS(inicio);
 
    cout<< dp[fin.x][fin.y] <<endl;
    system("pause");
    return 0;
}
I hope its not help that I'm wrong!!!
cronos ]]> C++ (Non Visual C++ Issues) carburo http://forums.codeguru.com/showthread.php?537131-Problem-in-Algorithm-Recursive calling a script from a makefile http://forums.codeguru.com/showthread.php?537097-calling-a-script-from-a-makefile&goto=newpost Sat, 18 May 2013 22:38:46 GMT Hello,

As advertized, I would like to call a script from a makfile to glean some information about the OS. What I more or less need is the OS name and version (CentOS-5.9, OPENSUSE-12.2, Cygwin, etc). I think I can get the rest of what I need from uname. The OS name and version doesn't seem to reside in any consistent place over the various Linux flavors. I also need to get the version of the gnu c compiler, since I think that may also require a bit more involved scripting than I would like to try out of make.

The main question is weather I can call a script out of make and have it return a value for a variable.

Something like,

OS := $(shell ./script_name)

Thanks,

LMHmedchem ]]> C++ (Non Visual C++ Issues) LMHmedchem http://forums.codeguru.com/showthread.php?537097-calling-a-script-from-a-makefile pls help, BHO (Browser Helper object) issue. http://forums.codeguru.com/showthread.php?537089-pls-help-BHO-(Browser-Helper-object)-issue.&goto=newpost Sat, 18 May 2013 14:55:42 GMT Hi all, I am totally new to developing BHO in c++, was thinking someone could give me a hand in source code or something to develop BHO (browser helper object). To inject html, javascript to a web browser All help will be greatly appreciated. Hi all,

I am totally new to developing BHO in c++, was thinking someone could give me a hand in source code or something to develop BHO (browser helper object). To inject html, javascript to a web browser

All help will be greatly appreciated. ]]> C++ (Non Visual C++ Issues) mindjos http://forums.codeguru.com/showthread.php?537089-pls-help-BHO-(Browser-Helper-object)-issue. Searching a vector of objects for pairs http://forums.codeguru.com/showthread.php?537047-Searching-a-vector-of-objects-for-pairs&goto=newpost Thu, 16 May 2013 18:35:56 GMT Hello all, Say I have a vector of objects and I want to return an object based on a pair of strings. The strings can be in either order Ie; A B==B A. In general, what do you think is the best way to do this? Thanks, T. Hello all,

Say I have a vector of objects and I want to return an object based on a pair of strings. The strings can be in either order Ie; A B==B A.

In general, what do you think is the best way to do this?

Thanks,
T. ]]> C++ (Non Visual C++ Issues) azeotrope http://forums.codeguru.com/showthread.php?537047-Searching-a-vector-of-objects-for-pairs Creating a Property (Get/Set) Class http://forums.codeguru.com/showthread.php?537037-Creating-a-Property-(Get-Set)-Class&goto=newpost Thu, 16 May 2013 12:47:35 GMT Title(L"New title!"); // Set MessageBox(NULL, instNoProp->Title(), NULL, 0); // Get --------- I could just write the following: Code: --------- instProp->Title = L"New title!"; // Set MessageBox(NULL, instProp->Title, NULL, 0); // Get --------- After about a week of playing around I came up with the following *Property* class, and another class named *InitProp* as a helper. Code: --------- #include template class Property; template class InitProp { typedef tProperty (tParent::*GET_PROP)(tParent*); typedef void (tParent::*SET_PROP)(tParent*, tProperty); public: InitProp(tParent *cParent, Property *cProperty, tProperty *&tVariable, GET_PROP Get_Property, SET_PROP Set_Property) { cProperty->m_Property = new tProperty; *cProperty->m_Property = NULL; tVariable = cProperty->m_Property; cProperty->m_Parent = cParent; cProperty->m_Copy = 0; cProperty->m_Get_Property = Get_Property; cProperty->m_Set_Property = Set_Property; }; }; template class Property { typedef tProperty (tParent::*GET_PROP)(tParent*); typedef void (tParent::*SET_PROP)(tParent*, tProperty); public: friend class InitProp; Property() { m_Parent = NULL; m_Set_Property = NULL; m_Get_Property = NULL; }; ~Property() { if (m_Copy-- == 0) delete m_Property; }; Property operator= (tProperty NewValue) { if (m_Set_Property != NULL) (m_Parent->*m_Set_Property)(m_Parent, NewValue); return *this; } Property(const Property& Prop) { ++m_Copy; }; operator tProperty() { if (m_Get_Property != NULL) return (m_Parent->*m_Get_Property)(m_Parent); else return NULL; }; private: int m_Copy; tParent *m_Parent; tProperty *m_Property; GET_PROP m_Get_Property; SET_PROP m_Set_Property; }; class Form { public: Property Title; Form() { InitProp pTitle(this, &Title, m_Title, &Form::g_Title, &Form::s_Title); }; private: LPCWSTR *m_Title; LPCWSTR g_Title(Form *Sender) { // User called Form.Title return *Sender->m_Title; }; void s_Title(Form *Sender, LPCWSTR NewValue) { // User set Form.Title = *Sender->m_Title = NewValue; }; }; int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { Form *frmMain; frmMain = new Form; frmMain->Title = L"This is just a test!"; MessageBox(NULL, frmMain->Title, NULL, 0); delete frmMain; return 0; } --------- So far this code only works with the LPCWSTR type (const wchar_t*). Unfortunately I got to this stage using only that type, and now when I try another type, such as int, it fails. When using the int type I believe it creates an error because the constructor of *InitProp* expects a type of pointer to be parsed. When I try using it with *int** type (the private variable then becoming int **m_Variable) it compiles, thought I cannot access the property like a normal *int*. My best guess from here is that I probably have to overload the *InitProp* constructor in a way that it can setup the *Property* classes for base-types and pointer-types, and then also modify the *Property* class to handle both. I'd appreciate any suggestions and input as I'm becoming lost in template->pointer-land. Thanks!]]> Hi there,

I've just recently moved from Visual Basic 6 over to C++ and decided that I would try and write a class to mimic the Get/Set behavior seen in a variety of other programming languages. So instead of just using an overloaded function, i.e:
Code:
class NoProp
{
    LPCWSTR m_Title;
public:
    void Title(LPCWSTR NewValue) {m_Title = NewValue;};
    LPCWSTR Title() {return m_Title;};
};

// ...

instNoProp->Title(L"New title!");  // Set

MessageBox(NULL, instNoProp->Title(), NULL, 0);  // Get
I could just write the following:
Code:
instProp->Title = L"New title!";  // Set

MessageBox(NULL, instProp->Title, NULL, 0);  // Get
After about a week of playing around I came up with the following Property class, and another class named InitProp as a helper.
Code:
#include <windows.h>

template <class tParent, class tProperty>class Property;

template <class tParent, class tProperty>
class InitProp
{
        typedef tProperty (tParent::*GET_PROP)(tParent*);
        typedef void (tParent::*SET_PROP)(tParent*, tProperty);

public:
        InitProp(tParent *cParent,
                        Property<tParent, tProperty> *cProperty,
                        tProperty *&tVariable,
                        GET_PROP Get_Property,
                        SET_PROP Set_Property)
        {
                cProperty->m_Property = new tProperty;
                *cProperty->m_Property = NULL;

                tVariable = cProperty->m_Property;

                cProperty->m_Parent = cParent;
                cProperty->m_Copy = 0;
                cProperty->m_Get_Property = Get_Property;
                cProperty->m_Set_Property = Set_Property;
        };
};

template <class tParent, class tProperty>
class Property
{
        typedef tProperty (tParent::*GET_PROP)(tParent*);
        typedef void (tParent::*SET_PROP)(tParent*, tProperty);

public:
        friend class InitProp<tParent, tProperty>;

        Property()
        {
                m_Parent = NULL;
                m_Set_Property = NULL;
                m_Get_Property = NULL;
        };

        ~Property()
        {
                if (m_Copy-- == 0)
                        delete m_Property;
        };

        Property operator= (tProperty NewValue)
        {
                if (m_Set_Property != NULL)
                        (m_Parent->*m_Set_Property)(m_Parent, NewValue);
               
                return *this;
        }

        Property(const Property& Prop)
        {
                ++m_Copy;
        };

        operator tProperty()
        {
                if (m_Get_Property != NULL)
                        return (m_Parent->*m_Get_Property)(m_Parent);
                else
                        return NULL;
        };

private:
        int m_Copy;
        tParent *m_Parent;
        tProperty *m_Property;
        GET_PROP m_Get_Property;
        SET_PROP m_Set_Property;
};

class Form
{
public:
        Property<Form, LPCWSTR> Title;

        Form()
        {
                InitProp<Form, LPCWSTR> pTitle(this, &Title, m_Title, &Form::g_Title, &Form::s_Title);
        };

private:
        LPCWSTR *m_Title;

        LPCWSTR g_Title(Form *Sender)
        {
                // User called Form.Title

                return *Sender->m_Title;
        };

        void s_Title(Form *Sender, LPCWSTR NewValue)
        {
                // User set Form.Title =

                *Sender->m_Title = NewValue;
        };

};

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
        Form *frmMain;
        frmMain = new Form;

        frmMain->Title = L"This is just a test!";

        MessageBox(NULL, frmMain->Title, NULL, 0);

        delete frmMain;

        return 0;
}
So far this code only works with the LPCWSTR type (const wchar_t*). Unfortunately I got to this stage using only that type, and now when I try another type, such as int, it fails. When using the int type I believe it creates an error because the constructor of InitProp expects a type of pointer to be parsed. When I try using it with int* type (the private variable then becoming int **m_Variable) it compiles, thought I cannot access the property like a normal int.

My best guess from here is that I probably have to overload the InitProp constructor in a way that it can setup the Property classes for base-types and pointer-types, and then also modify the Property class to handle both.

I'd appreciate any suggestions and input as I'm becoming lost in template->pointer-land.

Thanks! ]]> C++ (Non Visual C++ Issues) FrOzeN89 http://forums.codeguru.com/showthread.php?537037-Creating-a-Property-(Get-Set)-Class Problem about file handling!!! http://forums.codeguru.com/showthread.php?537031-Problem-about-file-handling!!!&goto=newpost Thu, 16 May 2013 05:09:08 GMT struct abc { char name[100]; int a; }; int main() { ofstream file; file.open("text.dat", ios::out | ios::binary); abc x; x.a = 2; cout<<"Enter name "; cin>>x.name; file.write((char*)&x,sizeof(struct abc)); file.close(); getch(); return 0; } ]]> Every time I write in file using ofstream it works fine except for one thing that when the file is re-opened after writing something and we try to add more data then previously added data is removed how to get rid of this.

<code>


struct abc
{
char name[100];
int a;
};


int main()
{


ofstream file;
file.open("text.dat", ios::out | ios::binary);


abc x;



x.a = 2;
cout<<"Enter name ";
cin>>x.name;



file.write((char*)&x,sizeof(struct abc));
file.close();

getch();
return 0;
}

</code> ]]> C++ (Non Visual C++ Issues) labeeb_ahmad http://forums.codeguru.com/showthread.php?537031-Problem-about-file-handling!!! Link time errors for static members http://forums.codeguru.com/showthread.php?537027-Link-time-errors-for-static-members&goto=newpost Thu, 16 May 2013 04:30:53 GMT init(m_navMesh, 2048); } public: dtNavMesh *loadAll(const std::string& path) { FILE* fp = fopen(path.c_str(), "rb"); if (!fp) return 0; // Read header. NavMeshSetHeader header; fread(&header, sizeof(NavMeshSetHeader), 1, fp); if (header.magic != NAVMESHSET_MAGIC) { fclose(fp); return 0; } if (header.version != NAVMESHSET_VERSION) { fclose(fp); return 0; } dtNavMesh* mesh = dtAllocNavMesh(); if (!mesh) { fclose(fp); return 0; } dtStatus status = mesh->init(&header.params); if (dtStatusFailed(status)) { fclose(fp); return 0; } // Read tiles. for (int i = 0; i < header.numTiles; ++i) { NavMeshTileHeader tileHeader; fread(&tileHeader, sizeof(tileHeader), 1, fp); if (!tileHeader.tileRef || !tileHeader.dataSize) break; unsigned char* data = (unsigned char*)dtAlloc(tileHeader.dataSize, DT_ALLOC_PERM); if (!data) break; memset(data, 0, tileHeader.dataSize); fread(data, tileHeader.dataSize, 1, fp); mesh->addTile(data, tileHeader.dataSize, DT_TILE_FREE_DATA, tileHeader.tileRef, 0); } fclose(fp); return mesh; } private: // By reference only, no memory consumption static dtNavMesh *m_navMesh; static dtNavMeshQuery* m_navQuery; static dtQueryFilter m_filter; static dtStatus m_pathFindStatus; }; --------- Error 3 error LNK2001: unresolved external symbol "private: static class dtNavMesh * NavMeshLoader::m_navMesh" (?m_navMesh@NavMeshLoader@@0PAVdtNavMesh@@A) D:\Jacky\Documents\Visual Studio 2010\Projects\PerfectSim\PerfectSim\PerfectSim\main.obj PerfectSim Error 2 error LNK2001: unresolved external symbol "private: static class dtNavMeshQuery * NavMeshLoader::m_navQuery" (?m_navQuery@NavMeshLoader@@0PAVdtNavMeshQuery@@A) D:\Jacky\Documents\Visual Studio 2010\Projects\PerfectSim\PerfectSim\PerfectSim\main.obj PerfectSim]]>
Code:
    class NavMeshLoader
    {
    public:
            NavMeshLoader()
            {
                    m_navMesh = loadAll("all_tiles_navmesh.bin");
                    m_navQuery->init(m_navMesh, 2048);
            }
    public:
            dtNavMesh *loadAll(const std::string& path)
            {
                    FILE* fp = fopen(path.c_str(), "rb");
                    if (!fp) return 0;
         
                    // Read header.
                    NavMeshSetHeader header;
                    fread(&header, sizeof(NavMeshSetHeader), 1, fp);
                    if (header.magic != NAVMESHSET_MAGIC)
                    {
                            fclose(fp);
                            return 0;
                    }
                    if (header.version != NAVMESHSET_VERSION)
                    {
                            fclose(fp);
                            return 0;
                    }
         
                    dtNavMesh* mesh = dtAllocNavMesh();
                    if (!mesh)
                    {
                            fclose(fp);
                            return 0;
                    }
                    dtStatus status = mesh->init(&header.params);
                    if (dtStatusFailed(status))
                    {
                            fclose(fp);
                            return 0;
                    }
                 
                    // Read tiles.
                    for (int i = 0; i < header.numTiles; ++i)
                    {
                            NavMeshTileHeader tileHeader;
                            fread(&tileHeader, sizeof(tileHeader), 1, fp);
                            if (!tileHeader.tileRef || !tileHeader.dataSize)
                                    break;

                            unsigned char* data = (unsigned char*)dtAlloc(tileHeader.dataSize, DT_ALLOC_PERM);
                            if (!data) break;
                            memset(data, 0, tileHeader.dataSize);
                            fread(data, tileHeader.dataSize, 1, fp);
                 
                            mesh->addTile(data, tileHeader.dataSize, DT_TILE_FREE_DATA, tileHeader.tileRef, 0);
                    }
         
                    fclose(fp);
         
                    return mesh;
            }

    private:
            // By reference only, no memory consumption
            static dtNavMesh *m_navMesh;
                     
            static dtNavMeshQuery* m_navQuery;

            static dtQueryFilter m_filter;

            static dtStatus m_pathFindStatus;
    };
Error 3 error LNK2001: unresolved external symbol "private: static class dtNavMesh * NavMeshLoader::m_navMesh" (?m_navMesh@NavMeshLoader@@0PAVdtNavMesh@@A) D:\Jacky\Documents\Visual Studio 2010\Projects\PerfectSim\PerfectSim\PerfectSim\main.obj PerfectSim
Error 2 error LNK2001: unresolved external symbol "private: static class dtNavMeshQuery * NavMeshLoader::m_navQuery" (?m_navQuery@NavMeshLoader@@0PAVdtNavMeshQuery@@A) D:\Jacky\Documents\Visual Studio 2010\Projects\PerfectSim\PerfectSim\PerfectSim\main.obj PerfectSim ]]> C++ (Non Visual C++ Issues) lucky6969b http://forums.codeguru.com/showthread.php?537027-Link-time-errors-for-static-members Member function pointer assignment http://forums.codeguru.com/showthread.php?537011-Member-function-pointer-assignment&goto=newpost Wed, 15 May 2013 16:13:10 GMT I have a class with member functions and a pointer like this:
Code:
class MyClass{
private:
    typedef void(MyClass::*memFnPtr_t) ();
public:
    memFnPtr_t fnptr;
    void fn1();
    void fn2();
};
Now in a regular function I create an instance of the class and try to assign the pointer:
Code:
MyClass mc;
mc.fnptr = &mc.fn1;
The compiler does not like it and suggests this instead:
Code:
mc.fnptr = &MyClass::fn1;
This seems to work but what if I have two instances of the class:
Code:
MyClass mc1, mc2;
How does the compiler know to distinguish between
Code:
mc1.fn1
and
Code:
mc2.fn1
when the assignment now looks identical:
Code:
mc1.fnptr = &MyClass::fn1;
mc2.fnptr = &MyClass::fn1;
?

:confused:

Thanks in advance! ]]> C++ (Non Visual C++ Issues) acppdummy http://forums.codeguru.com/showthread.php?537011-Member-function-pointer-assignment A Predator-Prey Simulation http://forums.codeguru.com/showthread.php?537005-A-Predator-Prey-Simulation&goto=newpost Wed, 15 May 2013 11:03:49 GMT Let there be two fishes named Kernighans and Ritchies. The only fish know to prey on Ritchies and to be able to digest them is the colour-blind Kernighan. The Kernighan has adapted to a diet of Ritchies, and won't prey on any other species. No other fish or sea animal could prey on the Ritchies.

So with he above information, could a simulation be created to calculate the two population at different time intervals. I have done something but i belive that i could be on the wrong track.

Some other information to follow would be:

The population of Kernighans and Ritchies can be fully determined by the population size of Kernighans and Ritchies. Suppose that in a given month the number of Kernighan is pop_k, and the population of Ritchies is pop_r. The population of Kernighans and Ritchies is measured in multiples of 1000. This means a population size of 1.0 corresponds to 1000 fish. For the number of Kernighans in the next month we have:

• The population pop_k decreases by alpha_k • pop_k. This is the number of Kernighans that would starve if there were no Ritchies to eat.
•The population pop_k increases by beta_k • pop_k • pop_r. This is the number of new Kernighans because they can feed on Ritchies.
•The population pop_k decreases by gamma_k • pop_k2. This decrease in the number of Kernighans is due to competition between Kernighans.

Hence, given a population pop_k, the population in the next month is
•pop_k - alpha_k • pop_k + beta_k • pop_k • pop_r - gamma_k.pop_k2
•If the result of this computation is smaller than 0.001, then there are no Kernighan fish left

For the number of Ritchies in the next month we have

The population pop_r increases by alpha_r • pop_r. This is the number of new Ritchies, if there were no Kernighan to eat them..
• The population pop_r decreases by beta_r • pop_k • pop_r. This is the number of Ritcchies eaten by Kernighans.
• The population pop_r decreases by gamma_r • pop_r2. This decrease in the number of Ritcchies tis due to competition between Ritchies.

Hence, given a population pop_r the population in the next month is

• pop_r + alpha_r.pop_r - beta_r.pop_k.pop_r - gamma_r.pop_r 2
• If the result of this computation is smaller than 0.001, then there are no Ritchie fish left.

Measurements have shown that the constants have the following values:
• alpha_k = 0.4;
• beta_k = 0.4
• gamma_k=0.036
• alpha_r = 0.2;
• beta_r = 0.2
• gamma_r=0.036 ]]> C++ (Non Visual C++ Issues) rockx http://forums.codeguru.com/showthread.php?537005-A-Predator-Prey-Simulation Circular Dependency error http://forums.codeguru.com/showthread.php?537003-Circular-Dependency-error&goto=newpost Wed, 15 May 2013 09:53:20 GMT Hi ,

I was doing Uni assignment ( not looking for a full solution ) had to use the start up code provided ( other wise this issue would not have come ),
when compiling the source I get the following error

"pms_program.h:54:56: error: expected declaration specifiers or ‘...’ before ‘CourseType’"

the code you are looking for in pms_course.h ( there is a circular dependency between pms.h , pms_course.h and pms_program.h)
Head tutor provided a GUARD however don't think it works properly

function prototype AppendProgram ( part of doubly linked list )



I have attached the full course code.

As much as I like I cannot change the structure of the startup code , I was hoping that someone know a solution or cam point me to the problem

please see attached zip file for the entire source code.

Thanks for Stopping by.
Attached Files
]]> C++ (Non Visual C++ Issues) aamir121a http://forums.codeguru.com/showthread.php?537003-Circular-Dependency-error Design advice required http://forums.codeguru.com/showthread.php?537001-Design-advice-required&goto=newpost Wed, 15 May 2013 09:47:58 GMT I am trying to design and implement a program that consists of two classes. The Base class A is purely for supporting class B. I do not want to be able to create an object of class A. When object B is created it inherits from class A. What is the best way to achieve this? I am trying to design and implement a program that consists of two classes. The Base class A is purely for supporting class B. I do not want to be able to create an object of class A. When object B is created it inherits from class A.

What is the best way to achieve this? ]]> C++ (Non Visual C++ Issues) Gerald Bates http://forums.codeguru.com/showthread.php?537001-Design-advice-required Read from file http://forums.codeguru.com/showthread.php?536935-Read-from-file&goto=newpost Sun, 12 May 2013 18:01:16 GMT #include // to read from file using namespace std; int main () { int latticeType; int dimX, dimY, dimZ; // number of translated cells along each axis float d; // lattice parameter float h; // second lattice parameter for HCP ifstream inputFile; // object of class 'ifstream' to read from it inputFile.open("input.txt", ios::in); // open 'input.txt' only for reading if (!inputFile){ cerr << "Unable to open input file"; return -1; } while (!inputFile.eof()){ inputFile >> latticeType; cout << latticeType << endl; if ( (latticeType!=1) && (latticeType!=2) && (latticeType!=3) ){ cerr << "Invalid value of lattice type" << endl; return -1; } inputFile >> d; cout << d << endl; if (latticeType==3){ inputFile >> h; cout << d << endl; } inputFile >> dimX; cout << dimX; inputFile >> dimY; cout << dimY; inputFile >> dimZ; cout << dimZ; } inputFile.close(); return 0; } --------- ]]> Hello.
I want my program to read variables from file "input.txt":
Quote:
Please choose the crystal lattice. Type 1 for BCC, 2 for FCC, and 3 for HCP: 2
Please enter lattice parameter (a): 1
For HCP please enter second lattice parameter (c): 1
Please enter the number of translated cells along X axis: 2
Please enter the number of translated cells along Y axis: 2
Please enter the number of translated cells along Z axis: 2
Moreover, I want program to read only the numbers after colon. How can I do it?
Code:
#include <iostream>#include <fstream> // to read from file
 
using namespace std;
 
int main ()
{
    int latticeType;
    int dimX, dimY, dimZ; // number of translated cells along each axis
    float d; // lattice parameter
    float h; // second lattice parameter for HCP
    ifstream inputFile; // object of class 'ifstream' to read from it
 
    inputFile.open("input.txt", ios::in); // open 'input.txt' only for reading
    if (!inputFile){
        cerr << "Unable to open input file";
        return -1;
    }
    while (!inputFile.eof()){
        inputFile >> latticeType;
        cout << latticeType << endl;
    if ( (latticeType!=1) && (latticeType!=2) && (latticeType!=3) ){
        cerr << "Invalid value of lattice type" << endl;
        return -1;
    }
        inputFile >> d;
        cout << d << endl;
        if (latticeType==3){
            inputFile >> h;
            cout << d << endl;
        }
        inputFile >> dimX;
        cout << dimX;
        inputFile >> dimY;
        cout << dimY;
        inputFile >> dimZ;
        cout << dimZ;
    }
    inputFile.close();
 
    return 0;
}
]]> C++ (Non Visual C++ Issues) ted_kingdom http://forums.codeguru.com/showthread.php?536935-Read-from-file Linked List problem http://forums.codeguru.com/showthread.php?536925-Linked-List-problem&goto=newpost Sat, 11 May 2013 16:55:50 GMT #include typedef struct Node { int data; struct Node *next; }node; void insert(node **ptrtohead, int val) { node *temp=(node*)malloc(sizeof(node)); *ptrtohead=temp; temp->data=val; temp->next=NULL; if(*ptrtohead != NULL) { temp->next=*ptrtohead; *ptrtohead=temp; } } void display(node *start) { while(start!=NULL) { printf("%d ",start->data); start= start->next; } } int main(int argc, char *argv[]) { node *head=NULL; insert(&head,10); insert(&head,20); display(head); system("PAUSE"); return 0; } --------- I don't know where is the problem, the output is infinite number of 10 !!!! Help is very much appreciated.]]>
Code:
#include <stdio.h>
#include <stdlib.h>


typedef struct Node
{
        int data;
        struct Node *next;
}node;

void insert(node **ptrtohead, int val)
{
  node *temp=(node*)malloc(sizeof(node));


                *ptrtohead=temp; 
                temp->data=val;

                temp->next=NULL;
         
          if(*ptrtohead != NULL)
          {
         
 
                temp->next=*ptrtohead;
                *ptrtohead=temp;
    }
   

}

void display(node *start)
{
        while(start!=NULL)
        {
       
                printf("%d ",start->data);
          start= start->next;
               
        }
}

int main(int argc, char *argv[])
{
 
 
  node *head=NULL;

        insert(&head,10);
        insert(&head,20);
        display(head);
 
  system("PAUSE");       
  return 0;
}
I don't know where is the problem, the output is infinite number of 10 !!!! Help is very much appreciated. ]]> C++ (Non Visual C++ Issues) dotnet13 http://forums.codeguru.com/showthread.php?536925-Linked-List-problem C++ easy school project, I need help http://forums.codeguru.com/showthread.php?536921-C-easy-school-project-I-need-help&goto=newpost Sat, 11 May 2013 09:40:45 GMT and then print to screen: Prime numbers in range 1 – 100 number of prime numbers: NN prime numbers: N N N N N N N N … N http://prntscr.com/14dmw1 (this is printscreen for another project, by operator I mean + - * /) Create program, which declarates field formed by matrix named OKTO[8;8]. Matrix’s elements will be saved to file named OKTO_DATA, from element 1,1 to 8,8 where 1,1 to 1,8 is one entry. For calculation value of elements you have to apply I+1 is double of I. http://wikisend.com/download/135354/moonlanding.jpg (link for image of flowchart) I beg anyone who can help me to help me, I know really nothing about programming, so I cant discuss this :( any help will save my pass to another year of high school, I would be very very very thankfull if anyone helps. PS: sorry for grammar or any english mistakes, it isnt my native language.]]> Hello there!

I am having trouble in school with some basic and easy (not for me) C++ programming.
If you could help me, I need codes for these programs to pass a high school grade. I study IT school, but I study multimedia and presentation, but they want basic programming too and I have no idea what to do with it.

Thanks for any help guys!

Create a program, which determines every prime number in interval <1;100> and then print to screen:
Prime numbers in range 1 – 100
number of prime numbers: NN
prime numbers: N N N N N N N N … N

http://prntscr.com/14dmw1 (this is printscreen for another project, by operator I mean + - * /)

Create program, which declarates field formed by matrix named OKTO[8;8]. Matrix’s elements will be saved to file named OKTO_DATA, from element 1,1 to 8,8 where 1,1 to 1,8 is one entry.
For calculation value of elements you have to apply I+1 is double of I.

http://wikisend.com/download/135354/moonlanding.jpg (link for image of flowchart)

I beg anyone who can help me to help me, I know really nothing about programming, so I cant discuss this :(
any help will save my pass to another year of high school, I would be very very very thankfull if anyone helps.
PS: sorry for grammar or any english mistakes, it isnt my native language. ]]> C++ (Non Visual C++ Issues) delivium http://forums.codeguru.com/showthread.php?536921-C-easy-school-project-I-need-help