Question

How to fill an array with the first N prime numbers in C

Answer 1

#include <stdio.h>
#include <stdbool.h>

#define N 10

bool isPrime(int num) {
    for (int i = 2; i <= num / 2; i++) {
        if (num % i == 0) {
            return false;
        }
    }

    return true;
}

void fill_array_with_N_prime_numbers(int arr[], int size) {
    int num = 1;

    for (int i = 0; i < size; i++) {
        while (!isPrime(++num)) {}

        arr[i] = num;
    }
}

int main() {
    int arr[N];

    fill_array_with_N_prime_numbers(arr, N);

    for (int i = 0; i < N; i++) {
        printf("%3d", arr[i]);
    }

    return 0;
}



/*
run:

  2  3  5  7 11 13 17 19 23 29

*/

 

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