Question

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

Answer 1

#include <stdio.h>
#include <math.h>

_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
		}
	}
	
	printf("%d", sum);

	return 0;
}
 

 
 
/*
run:
 
35

*/

 

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