struct temp {
     int a;
 };
 int pass(struct temp **); //passing var
 int pass(struct temp ** var1) { //passing var
     (* var1)->a = 100;
     return 0;
 };
 int main() {
     struct temp * var2 = NULL;
     var2->a = 10;
     printf("nbefore pass var2->a = %d", var2->a);
     pass(&var2);
     printf("nafter pass var2->a = %d", var2->a);
     return 0;
 }