Question

How to sum of all the prime numbers in an array with C++

Answer 1

#include <iostream>
#include <cmath>
 
using namespace std;
 
bool isPrime(int n) {
    if (n == 0) return 0;
    if (n == 1) return 0;
    for (int i = 2; i <= sqrt(n); i++) {
        if (n % i == 0)
            return 0;
    }
    return 1;
} 
 
int main() {
    int arr[] = {4, 8, 17, 5, 9, 22, 21, 13, 18, 99};
    int len = sizeof(arr) / sizeof(int), sum = 0;
  
    for (int i = 0; i < len; i++) {
        if (isPrime(arr[i])) {
            sum += arr[i]; // 17 5 13
        }
    }
    cout << sum;
}

 
 
/*
run:
 
35
 
*/

 

70+ SQL courses for beginners and professionals