Answer 4 Looping CPP

#include <bits/stdc++.h>
using namespace std;
#define FIO                           \
    ios_base::sync_with_stdio(false); \
    cin.tie(NULL);                    \
    cout.tie(NULL);

int main()
{
    FIO;
    int a, b;
    cin >> a >> b;
    for (int i = a; i <= b; i++) {
        // Skip 0 and 1 as they are
        // neither prime nor composite
        if (i == 1 || i == 0)
            continue;

        // flag variable to tell
        // if i is prime or not
        bool flag = 1;

        for (int j = 2; j <= i / 2; ++j) {
            if (i % j == 0) {
                flag = 0;
                break;
            }
        }

        // flag = 1 means i is prime
        // and flag = 0 means i is not prime
        if (flag == 1)
            cout << i << " ";
    }
}