缩进

#include <iostream>
#include <cmath>

bool isPrime(int num) {
if (num <= 1) {
return false;
}
int limit = std::sqrt(num);
for (int i = 2; i <= limit; ++i) {
if (num % i == 0) {
return false;
}
}
return true;
}

int main() {
for (int n = 100; n <= 999; ++n) {
if (isPrime(n)) {
stdcout << n << stdendl;
}
}
return 0;
}