What is wrong with my code(what should be there for negative exponents)[N.B.:you can't use power function.]

Question

#include <iostream>
int is_prime();
using namespace std;

int main() {
int num;
cin >> num; // Reading input from STDIN
for(int i=2;i*i<=num;i++){
if(is_prime(i)==1) {
cout<<i<<" ";
}
return 0;
}

int is_prime(int x){
for(int i=2;i*i<=x;i++){
if(i%x==0) return 1;
else return 0;
}

}

Answer 1

According to your code logic, it prints whatever number which isn't prime. Also, your function prototype signature does not tally with the definition. int is_prime(int); The way the braces are placed is also wrong. The loop condition in main is wrong. The return statement in the function which checks for prime is also wrong.

Answer 2

#include <iostream>

using namespace std;

int is_prime(int);

int main() {
int num;
cin >> num;
for(int i=2; i <= num; i++)
if(is_prime(i))
cout<<i<<" ";

return 0;
}

int is_prime(int x) {
for(int i=2;i*i<=x;i++)
if(x%i==0) return 0;
return 1;
}