﻿ C Program: Check if a given number is a Kaprekar number

# C Exercises: Check whether a given number is a Kaprekar number or not

## C Numbers: Exercise-6 with Solution

Write a program in C to check whether a given number is a Kaprekar number or not.

Test Data
Input a number: 45

Sample Solution:

C Code:

``````# include <stdio.h>
# include <stdbool.h>
# include <math.h>

bool chkkaprekar(int n)
{
if (n == 1)
return true;
int sqr_n = n * n;
int ctr_digits = 0;
while (sqr_n)
{
ctr_digits++;
sqr_n /= 10;
}
sqr_n = n*n;
for (int r_digits=1; r_digits<ctr_digits; r_digits++)
{
int eq_parts = pow(10, r_digits);

if (eq_parts == n)
continue;
int sum = sqr_n/eq_parts + sqr_n % eq_parts;
if (sum == n)
return true;
}
return false;
}
int main()
{
int kpno;
printf("\n\n Check whether a given number is a Kaprekar number: \n");
printf(" -------------------------------------------------------\n");
printf(" Input a number: ");
scanf("%d",&kpno);
if (chkkaprekar(kpno)==true)
{
printf("%d is a Kaprekar number. \n",kpno);
}
else
{
printf("%d is not a Kaprekar number. \n",kpno);
}
}
```
```

Sample Output:

``` Input a number: 45
45 is a Kaprekar number.
```

Pictorial Presentation:

Flowchart:

C Programming Code Editor:

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿

## C Programming: Tips of the Day

Why do C and C++ compilers allow array lengths in function signatures when they're never enforced?

It is a quirk of the syntax for passing arrays to functions.

Actually it is not possible to pass an array in C. If you write syntax that looks like it should pass the array, what actually happens is that a pointer to the first element of the array is passed instead.

Since the pointer does not include any length information, the contents of your [] in the function formal parameter list are actually ignored.

Ref : https://bit.ly/3fhlvdH