c - Getting segmentation fault while scanning an integer value -

though strange, getting segmentation fault while scanning integer value.

here program :

#include <stdio.h> #include <stdlib.h> #include <string.h>  int main() {     int t,n,i,j;     char c;     int grid[1000][1000],right[1000][1000],down[1000][1000];     scanf("%d",&t);     printf("hello\n");     while(t--)     {         scanf("%d",&n);          memset(right, 0, sizeof(int) * 1000 *1000);         memset(down, 0, sizeof(int) * 1000 *1000);          for(i=0;i<n;i++)         {             for(j=0;j<n;j++)             {                 scanf("%c",&c);                 printf("char = %c\n", c);                 if(c == '.')                     grid[i][j] = 1;                 else                     grid[i][j] = 0;             }         }         for(i=0;i<n;i++)         {             for(j=0;j<n;j++)             {                 printf("%d",grid[i][j]);             }         }     }     return 0; } 

doing gdb shows segmentation fault @ line scanf("%d",&t);. cannot figure out how happening?

[using gcc-4.8.4 on linux 32-bit machine ]

the problem arrays: grid, right , down big fit stack.

as far reason no compile error concerned:

because there nothing wrong code in terms of syntax or semantics. linker not have problem.

the problem arises when loader tries load program , allocate memory on stack. stack 8 mb on linux systems , arrays surpass that.

you can make them static (as suggested in comments) static members allocated on bss or data segment. in reality need rethink if need such big arrays.