Bunch of errors.

[dietao234]

Whats wrong with this code:

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include <vector>
using namespace std;

struct rec {
int height;
int width;
};
vector<struct rec[4]> gen(struct rec arr []){
vector<struct rec[4]> generated;
for(int a = 0; a < 4; a++){
for(int b = 0; b < 4; b++){
if(b != a){
for(int c = 0; c < 4; c++){
if(c!=a && c!= b){
for(int d = 0; d < 4; d++){
if(d!=a&&d!=b&&d!=c){
struct rec array [4];
array[0] = arr[a];
array[1] = arr[b];
array[2] = arr[c];
array[3] = arr[d];
generated.push_back(array);
}
}
}
}
}
}
}
return generated;
}

int main(){

}


I get almost a screen-full of errors when I try to compile this in the terminal. Any help would be greatly appreciated. Thanks in advance

[Russco]

You cant have a vector of array types like that. The type held by the vector must be copyable and assignable.

Whats wrong with this code:

Its not tagged!

[Paul McKenzie]

Whats wrong with this code:

The code is a combination of an attempt of C++, mixed with 'C'. Regardless, it's wrong (and it wasn't placed in code tags).

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include <vector>
#include <array>

using namespace std;

struct rec 
{
    int height;
    int width;
};

typedef tr1::array<rec, 4> Rec4;
typedef std::vector<Rec4> Rec4Vector;

Rec4Vector gen(rec arr [])

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include <vector>

using namespace std;

struct rec 
{
    int height;
    int width;
};

struct Rec4
{
     rec recArray[4];
};

typedef std::vector<Rec4> Rec4Vector;

Rec4Vector gen(rec arr [])

Take your pick. If you have the tr1::array class (or equivalent array template class), use the first example.

If you don't have the class, then fake it out by creating a struct that contains an array of 4 elements (and change your code accordingly). That is what the second example represents.

Regards,

Paul McKenzie

[monarch_dodra]

Given the nature of your four-deep-for-loop, you may want to look into algorithm std::next_permutation. It should generate the same arrays you are getting with your loops.

Also, consider using "continue" keyword, instead of nesting your ifs, you'll get smaller and more manageable code:

//Your loop
for(int a = 0; a < 4; a++){
    for(int b = 0; b < 4; b++){
    if(b != a){
        for(int c = 0; c < 4; c++){
            if(c!=a && c!= b){
                for(int d = 0; d < 4; d++){
                    if(d!=a&&d!=b&&d!=c){
                        struct rec array [4];
                        array[0] = arr[a];
                        array[1] = arr[b];
                        array[2] = arr[c];
                        array[3] = arr[d];
                        generated.push_back(array);
                        }
                    }
                }
            }
        }
    }
}

//Your loop using continue
for(int a = 0; a < 4; a++){
    for(int b = 0; b < 4; b++){
        if(b == a){ continue }
        for(int c = 0; c < 4; c++){
            if(c==a || c== b){ continue }
            for(int d = 0; d < 4; d++){
                if(d==a || d==b || d==c){ continue }
                struct rec array [4];
                array[0] = arr[a];
                array[1] = arr[b];
                array[2] = arr[c];
                array[3] = arr[d];
                generated.push_back(array);
            }
        }
    }
}

//using next_permutation
int index[4] = {0,1,2,3};
int* beg = index;
int* end = index+4;
do {
    struct Rec4 array;
    for(int i = 1; i<4; ++i)
    {
        array.rec[i] = arr.rec[index[i]];
    }
    generated.push_back(array);
} while ( next_permutation(beg,end) );