C Program for Magic Number – Pencil Programmer

A magic number is that number whose sum of its digits is when multiplied by the reverse of the sum of its digits gives back the same number.

E.g 1729

Input a number.
Copy the original number into another variable i.e temp.
Using while loop and mod (%) operator, add the digits of temp and store it in sumOfDigits.
Copy the value of sumOfDigits into temp.
Using while loop on temp, compute reverse of temp (i.e of sumOfDigits) and store it in rev.
Check if rev == sumOfDigits.
If Yes, then the given number is Magic number else not.

#include <stdio.h>

#include <stdlib.h>

int main()

{

int num, temp, rev=0, digit, sumOfDigits=0;

printf("Enter a Number \n");

scanf("%d",&num);

temp = num;

//Calculating Sum of digits

while(temp > 0){

sumOfDigits += temp % 10; //Extracting least significant digit & Adding

temp = temp / 10; // Removing least significant digit

}

//Computing reverse of Sum of Digits of num

temp = sumOfDigits;

while( temp > 0){

rev = rev*10 + temp % 10; // Concatenating lest significant digit for calc. reverse of sumOfDigits

temp = temp / 10;

}

if(rev*sumOfDigits == num)

printf("Magic Number \n");

else

printf("Not a Magic Number \n");

return 0;

}

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