C Exercises: Check whether a number is Lychrel number or not

C Numbers: Exercise-8 with Solution

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

Test Data
Input a number: 196

Sample Solution:

C Code:

# include <stdio.h>
# include <stdbool.h>
# include <stdlib.h>

bool palindrome ( unsigned long long int i );
unsigned long long int reverse ( unsigned long long int i );
bool lychrel ( unsigned long long int i );

int main ( void )
{
	unsigned long long int i=0;
	int count=0,num1;
  printf("\n\n Check whether a given number is a Lychrel number or not: \n");
  printf(" -------------------------------------------------------------\n");
  printf(" Input a number: ");
  scanf("%d",&num1);
		if(lychrel(num1))
		{
	printf(" The given number is Lychrel.\n\n");
		}
		else
		{
			printf(" The given number is not Lychrel.\n\n");
		}
	return 0;
}
bool lychrel ( unsigned long long int i )
{
	int j; /*iteration counter*/
	bool lychrel = true;
	i = i + reverse ( i );

	for ( j = 1; j <= 30 ; j++ )
	{
		if ( palindrome ( i ) )
		{
			lychrel = false;
			break;
		}
		i = i + reverse ( i );
	}

	return lychrel;
}
unsigned long long int reverse ( unsigned long long int i )
{
	unsigned long long int ret = 0;
	while ( i != 0 )
	{
		ret *= 10;
		ret += i % 10;
		i /= 10;
	}
	return ret;
}

bool palindrome ( unsigned long long int i )
{
	return ( i == reverse ( i ) );
}

Sample Output:

 Input a number: 196                                                                                          
 The given number is Lychrel.

Pictorial Presentation:

Flowchart:

C Programming Code Editor:

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