[C언어 #18] 입력한 숫자 소수 판별

C언어 입력한 숫자 소수 판별

 

 

Check whether input number is prime number

 

/* Is input number prime number */
#include <stdio.h>
#include <stdbool.h>
#include <math.h>
 
/* Get input number */
int getInputNumber() {
    int input = 0;
    printf("Input an integer: ");
    scanf("%d", &input);
    return input;
}
 
/* Check whether input number is prime. */
bool isPrime(int num) {
    int max = sqrt(num);
    bool b = true;
    for (int i = 2; i <= max; i++) {
        if (num % i == 0) {
            b = false;
            break;
        }
    }
    return b;
}
 
/* Print result*/
void printResult(int num, bool b) {
    if (b) printf("Input number %d is prime.\n", num);
    else printf("Input number %d is not prime.\n", num);
}
 
/* Run methods */
void run() {
    int num = getInputNumber();
    printResult(num, isPrime(num));
}
 
int main() {
    run();
    return 0;
}