## Introduction

I have used Code::blocks 12 compiler for debugging purpose. But you can use any C programming language compiler as per your availability.

#include <stdio.h> #include <math.h> int checkPrimeNumber(int n); int checkArmstrongNumber(int n); int main() { int num, flag; printf("Enter a positive integer: "); scanf("%d", &num); // Checking prime number flag = checkPrimeNumber(num); if (flag == 1) printf("%d is a prime number.\n", num); else printf("%d is not a prime number.\n", num); // Checking Armstrong number flag = checkArmstrongNumber(num); if (flag == 1) printf("%d is an Armstrong number.", num); else printf("%d is not an Armstrong number.",num); return 0; } //function to check prime number int checkPrimeNumber(int num) { int i, flag = 1; for(i=2; i<=num/2; ++i) { // condition for non-prime number if(num%i == 0) { flag = 0; break; } } return flag; } //function to check Armstrong Number int checkArmstrongNumber(int number) { int originalNumber, remainder, result = 0, num = 0, flag; originalNumber = number; while (originalNumber != 0) { originalNumber /= 10; ++num; } originalNumber = number; while (originalNumber != 0) { remainder = originalNumber%10; result += pow(remainder, num); originalNumber /= 10; } // condition for Armstrong number if(result == number) flag = 1; else flag = 0; return flag; }