why do we need to define an array iwth its numbr of elemnts in c code example

Example: create n number of arrray in c

int n,i;

//enter n

int **array = malloc(sizeof(int*)*n);

for(i=0;i<n;i++)
  array[i] = malloc(sizeof(int)*64);

 /* Do Stuffs*/


/* Free Memory */  
for(i=0;i<n;i++)
  free(array[i]);

free(array);