c - Prime numbers using Interface -

how write code prime number generator using specified interface.

i think asked.

int isprime(int i) {     int j;     if(i == 1 || == 2)             return 1;     if(i % 2 == 0)             return 0;      (j = 3; j < sqrt(n); j += 2)             if (i % j == 0)                     return 0;      return 1; }  void generator(int start, int end) {     int i;     if(start > end) {             int temp = start;             start = end;             end = start;     }      (i = start; i<=end; i++)             if(isprime(i))                     printf("%d\n", i); }  int main() {     generator(7900, 7920);     return 0; }