int is_prime_number(int n) {
  if (n < 0) { // treat neg. inputs as their positive counterparts
    n *= -1;
  }
  
  if (n == 1) { // 1 is a special case
    return 0;
  }

  // for all other cases
  return check_if_prime(n, 2);
}
int check_if_prime(int n, int m) {
  if (m == n) { // base case: all factors tested, n is prime
    return 1;
  }

  if (n % m == 0) { // base case: n divisible by m, n is not prime
    return 0;
  }

  // else: n is not divisible by m, but there are other factors to test; call again
  return check_if_prime(n, m + 1);
}
int is_prime_number(int n) {
  if (n < 0) {
    n *= -1;
  }
  
  if (n == 1) {
    return 0;
  }

  //else
  return check_if_prime(n, n/2);
}
Ejemplo n.º 4
0
int main(){
  int extra; char *len = "prime";
int num;
     int is_prime,i;
  for(i = 0;i < 10;i++){printf("Introduceti numar:");
	       scanf("%d", &num);
      is_prime = check_if_prime(num);
        if(is_prime)
            printf("is %s\n",len); else printf("is not %s\n",len);
     extra = get_sum(num);
   printf("sum (1..%d) is %d\n",num,extra);
 }

  return 0;
}
int check_m_by_p(int n, int m, int p) {
  //printf("checking m by p, m is %d, p is %d\n", m, p);
  if (p == 1) {
    return check_if_prime (n, m - 1);
  }

  // else
  if (n / m == p) {
    //printf("checking m by p\n");
    if (m * p == n) {
      return 0;
    }
  }

  // ELSE
  return check_m_by_p(n, m, p - 1);
}
Ejemplo n.º 6
0
void main(void)
{

  int i = 2;
  int count = 0;
  int array[WHICHPRIME];

  while (count < WHICHPRIME)
  {
    if (check_if_prime(i) == 0)
    {
       printf("%d is a prime number.\n",i);
       count++;
       array[count] = i;
    }
    else
       printf("%d is not a prime number.\n",i);
    i++;
  }

  printf("Prime #%d is %d.\n",WHICHPRIME,array[count]);
//  printf("Prime #%d between 1 and %d is %d.\n",WHICHPRIME,TOTAL,array[WHICHPRIME]);
}