# C Program to Check Whether a Number is Magic Number or Not

• Write a C program to check whether a number is magic number or not.
• Algorithm to check magic number.

Here is the algorithm to check whether a number is magic number or not

• Take a number N as input from user.
• Find the sum of the digits of N(Lets call it digitSum).
• Reverse the digits of digitSum(Lets call it reverse).
• If product of digitSum and reverse is equal to the original number N, then N is magic number otherwise not a magic number.

### C program to check whether a number is magic number or not

This program implements the above mentioned algorithm to check a number is magic number or not. It user two user defined helper function:

• getReverse : Reverses the digits if passed number and returns it.
• getSumOfDigit : Returns the sum of digits of passed number.

/*
* C program to check a number is magic number or not
*/
#include<stdio.h>
#include<conio.h>

int getReverse(int num);
int getSumOfDigit(int num);

int main () {
int num, digitSum, reverse;

printf("Enter a number\n");
scanf("%d", &num);

/* get sum of digits of input number */
digitSum = getSumOfDigit(num);

/* reverse the digits of digitSum*/
reverse = getReverse(digitSum);

if ((digitSum * reverse) == num) {
printf("%d is a Magic Number\n", num);
} else {
printf("%d is not a Magic Number\n", num);
}

getch();
return 0;
}

/* Function to reverse an integer  */
int getReverse(int num) {
int r = 0;
while (num > 0) {
r = (r * 10) + (num % 10);
num = num / 10;
}
return r;
}

/* Function to calculate sum of digits of a number*/
int getSumOfDigit(int num){
int sum = 0;
while(num != 0){
/* num%10 gives least significant digit of num */
sum = sum + num%10;
num = num/10;
}
return sum;
}

Program Output

Enter a number
1234
1234 is not a Magic Number

Enter a number
1729
1729 is a Magic Number