General Protection Error in C++ code

[onkarbulbule]

Hi I am trying to do a program on convolution, that is, multiplying 2 non-multipliable matrices. Here is the code. I even know where I'm getting an error. It's on line 20. Please help me out. Why am I getting this error?

#include<iostream.h>
#include<stdio.h>
#include<conio.h>
 
 
void main()
{
 int a[5][5], b[10][10], t[20][10][10], res[10][10];
 int i, j, k, x;
 cout<<"Enter matrix 1 : \n";
 for(i=0; i<3; i++)
  for(j=0; j<3; j++)
    cin>>a[i][j];
 cout<<"Enter matrix 2 : \n";
 for(i=1; i<5; i++)
  for(j=1; j<5; j++)
    cin>>b[i][j];
 for(i=0, j=0; j<6; j++)
 {
  b[i][j] = b[j][i] = b[5-i][j] = b[j][5-i] = 0;
 }
 for(x=0; x<16; x++)
 {
  res[x/4][x%4]=0;
  for(i=0; i<3; i++)
  {
    for(j=0; j<3; j++)
    {
     t[x][i][j] = 0;
     for(k=0; k<3; k++)
     {
      t[x][i][j] += a[i][k]*b[k+x/4][j+x%4];
     }
     res[x/4][x%4] += t[x][i][j];
    }
  }
 
 }
 
 cout<<"The resultant matrix is :\n";
 for(i=0; i<4; i++)
 {
  for(j=0; j<4; j++)
  {
    cout<<res[i][j]<<" ";
  }
  cout<<endl;
 }
 
 getch();
}

[onkarbulbule]

PS -
The error is in the for loop probably in the line -
b[i][j] = b[j][i] = b[5-i][j] = b[j][5-i] = 0;
Please help!

[Gobi Sakthivel]

Can u explain what is meant by convolution, and give some sample input and output to make it clear.

[Anas Mosaad]

Convolution is a term used in pattern matching to determine the overlaps between two input matrices. For example, if you are searching for letter A in a photo, you would multiply the A matrix in different pieces from the photo matrix until you detect the overlaps (i.e. matches). Hope it's clear now.

[Banfa]

Trying out your code unmodified and inputting 1 for all items produces a result with no crash.

Visual inspection of the code shows no reason for a crash to happen.

Without further information I am not sure there is much more we can do.