Dealing with large arrays without getting runtime error

Question

I am getting runtime error when I used array of size 10^5*10^5 (ex. int a[100000][100000]. As this array is consuming more memory, this may be one one of the reason

Answer 1

Three ways to declare the large array int a[100000][100000] are:

1. Make the large array global

2. Make the large array static:

   static int a[100000][100000];
   

3. Use malloc/calloc and dynamically allocate the large array:

   int **a;
   a=malloc(sizeof(int*)*100000);
   for(int i=0;i<100000;i++)
       a[i]=malloc(sizeof(int)*100000);
   
   /*Use the array*/
   
   for(int i=0;i<100000;i++)
       free(a[i]);
   free(a);