Pass value from one function to another

In this program, I have to ask the user for an employee, then the program will check to see if the file for that employee exist, if it doesnt then it will automatically create the file.

ReadNew function reads the file....check to see if it exist

CreateNew function creates a new file.

In my code I have no problem with the first part of reading file.. and my createnew function works in other programs where I am asking for input of file name to create the file name. However in this code I cannot figure how to automatically pass the input filename from the ReadNew function to the CreateNew function. I can't ask the user to enter the name a second time, so I have to pass the input filename into both functions

Here is my code.

Code:

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//Create a file, append to it, and read it.

#include <iostream>
#include <fstream>
#include <string.h>
#include <stdio.h>
using namespace std;
char filename[256];
string n;
string filelist;
void CreateNew(ofstream & FileNew);
void ReadNew(ifstream & FileGet);
void AppendNew(ofstream & FileApp);
int response;
char trash[2];
int fileyes=0;


//Main
int main()
{        ofstream FileCreate;
    ifstream FileRead;
    ofstream fileAppend;
 
        cout<<"Do you want to find information about an employee? (0 for yes, 1 for no) ";
        cin>>response;
        cin.getline(trash, 2);
        while(response == 0)
       
        {
                ReadNew(FileRead);
       
                if(fileyes==1)
                {
                        CreateNew(FileCreate);
                }       
                cout<<"fileyes = "<<fileyes<<endl;       
                       
        cout<<"enter another name (0 for yes, 1 for no)  ";
        cin>>response;
}       
                       

    return 0;
}



//functions

void CreateNew(ofstream & FileNew)//Create file
{
    char filename[256];
    string name;
    FileNew.open(filename);
    name = filename;
    if(FileNew.is_open())
    {
            cout<<"\n";
        cout<<name<<".txt file is successfully created!\n";
                cout<<"\n";
                fileyes=0;
               
    }
    else
        cout<<"can not open a file...\n"<<endl;
}


void ReadNew(ifstream & FileGet)// Read file
{  char filename[256];
        string name;
        char newname;
    string line;
    fileyes=0;
  cout<<"Enter file name to extract info.: ";
  cin.getline(filename, 256);
  name = filename;
    FileGet.open(filename);
    if(FileGet.is_open())
    {
        while(1)
        {
            getline(FileGet, line);
            cout<<line<<endl;

            if(FileGet.eof())
                break;
        }
    }
    else
            fileyes=1;
      cout<<"read1\n ";
}

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If you want to request the name of the file in ReadNew, then the name can either be passed back to the calling routine as a return value from the function, or as a reference parameter to the function. Alternatively, but not recommended, name could be another global variable.

A couple of points to note. For c++, the include names are cstring and cstdio, not string.h and stdio.h. Also, it is not considered good practice to have your variables defined as global. Good practice is to define them near to where they are first used with as small a scope as possible. Rather than have the file functions set a global variable, it would be more usual for these functions to return a type bool indicating whether success or not.

eg

Code:

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bool ReadNew(ifstream& FileGet, string& name)

---

Code:

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#include <string.h>

---

I guess you wanted the <string> header.

Code:

---

char filename[256];
string n;
string filelist;
void CreateNew(ofstream & FileNew);
void ReadNew(ifstream & FileGet);
void AppendNew(ofstream & FileApp);
int response;
char trash[2];
int fileyes=0;

---

As 2kaud mentioned, using global variables is bad practice. Especially because you are using them to pass values between functions, which will prevent you from learning the proper way to pass values between functions and how to design your program. IMO it's also bad design to mix input/output with application logic. It would be better to split these things into separate functions. So, the outline of your program could be something like

Code:

---

std::string fileName = getFileName();
std::ifstream ifs(fileName);
if (!ifs.is_open()) {
    createFile(fileName);
    ifs.open(fileName);
}
displayContents(ifs);

---

Code:

---

        cout<<"Do you want to find information about an employee? (0 for yes, 1 for no) ";
        cin>>response;

---

What happens when the user inputs a letter? See Why does my program go into an infinite loop when someone enters an invalid input character?

Note that <string> and <cstring> are not the same.

<cstring> is C++'s name for the old C <string.h>. It contains functions to operate on char*-style strings, like strcat, strcpy, etc.

<string> is the C++ string class. It's much safer, easier, and all around better to use than char*s in most cases.