C++ to print to a file with cases and arrays - c++

Question

Ok, so this program has been shortened to make it easier to read. There would obviously be more case statements to go along with the amount of variables there are. My question is why does my program get an error every time it runs. It is fine when it compiles but not when I run it.
#include <iostream>
#include <fstream>
#include <cmath>
#include <string>
using namespace std;
int main()
{
string thearray[22960];
char bigfor[10];
int arrayvar = 0;
int finishedarray;
int a;
int b;
int c;
int d;
int e;
int f;
int g;
int h;
int i;
int j;
// Constants
int variable1 = 0;
int variable2 = 1;
int variable3 = 2;
int variable4 = 3;
int variable5 = 4;
int variable6 = 5;
int variable7 = 6;
int variable8 = 7;
int variable9 = 8;
int variable10 = 9;
for (a = 0; a < 36; a++)
{
switch (a)
{
case 0:
bigfor[variable1] = '0';
break;
case 1:
bigfor[variable1] = '1';
break;
case 2:
bigfor[variable1] = '2';
break;
case 3:
bigfor[variable1] = '3';
break;
case 4:
bigfor[variable1] = '4';
break;
case 5:
bigfor[variable1] = '5';
break;
case 6:
bigfor[variable1] = '6';
break;
case 7:
bigfor[variable1] = '7';
break;
case 8:
bigfor[variable1] = '8';
break;
case 9:
bigfor[variable1] = '9';
break;
}
thearray[arrayvar] = bigfor[variable1] + bigfor[variable2] + bigfor[variable4] +
bigfor[variable5] + bigfor[variable6] + bigfor[variable7] +
bigfor[variable8] + bigfor[variable9] + bigfor[variable10];
arrayvar = arrayvar + 1;
}
finishedarray = arrayvar + 1;
ofstream myfile;
myfile.open("codes.txt");
for (arrayvar = 0; a < finishedarray; a++)
{
myfile << thearray[arrayvar] << endl;
}
myfile.close();
return 0;
}

Answer 1

One problem is that you are reading uninitialized values here:
thearray[arrayvar] = bigfor[variable1]+ bigfor[variable2] + bigfor[variable4] +
bigfor[variable5] + bigfor[variable6] + bigfor[variable7] + bigfor[variable8] +
bigfor[variable9] + bigfor[variable10];
This is undefined behaviour. At this point in the program, only bigfor[variable1] is initialized.
Whatever you are trying to do, I have a feeling there is a simpler way to do it.

Answer 2

The problem was the addition you were doing. The addition will only add the integer-encoded values of the ASCII characters, and result in an integer. This will cause an error because you can't assign an integer to a std::string.
In addition to #juanchopanza's answer, your code can be improved substantially. For example, instead of listing out the indices manually, you can do this instead within your for loop:
std::string bigfor;
for (int a = 0; a < 36; ++a)
{
bigfor += (a + 48);
}
std::ofstream myfile("codes.txt");
for (int i = 0; i < bigfor.size(); ++i)
{
myfile << bigfor[i] << std::endl;
}