Programming Example
C Program to Check Prime and Armstrong Number
In this section you will learn how to check Check Prime and Armstrong Number using c programming language
/*
Author: Atnyla Developer
*/
#include "stdio.h"
#include "math.h"
int checkPrimeNumber(int n);
int checkArmstrongNumber(int n);
int main()
{
int n, flag;
printf("Enter a positive integer: ");
scanf("%d", &n);
// Check prime number
flag = checkPrimeNumber(n);
if (flag == 1)
printf("%d is a prime number.\n", n);
else
printf("%d is not a prime number.\n", n);
// Check Armstrong number
flag = checkArmstrongNumber(n);
if (flag == 1)
printf("%d is an Armstrong number.", n);
else
printf("%d is not an Armstrong number.",n);
return 0;
}
int checkPrimeNumber(int n)
{
int i, flag = 1;
for(i=2; i <= n/2; ++i)
{
// condition for non-prime number
if(n%i == 0)
{
flag = 0;
break;
}
}
return flag;
}
int checkArmstrongNumber(int number)
{
int originalNumber, remainder, result = 0, n = 0, flag;
originalNumber = number;
while (originalNumber != 0)
{
originalNumber /= 10;
++n;
}
originalNumber = number;
while (originalNumber != 0)
{
remainder = originalNumber%10;
result += pow(remainder, n);
originalNumber /= 10;
}
// condition for Armstrong number
if(result == number)
flag = 1;
else
flag = 0;
return flag;
}<b>Output 1:</b>
Enter a positive integer: 407
407 is not a prime number.
407 is an Armstrong number.
<b>Output 2:</b>
Enter a positive integer: 25
25 is not a prime number.
25 is not an Armstrong number.
checkPrimeNumber() and checkArmstrongNumber() are created.
The checkPrimeNumber() returns 1 if the number entered by the user is a prime number. Similarly, checkArmstrongNumber() returns 1 if the number entered by the user is an Armstrong number. First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.
After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.