The program that tests whether a number is divisible by 11 and 9 or not using recursion

C Programming Language Recursion in c (Article) Recursion in c (Program)

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Program:

#include<stdio.h>
int divisibleBy9(long int x);
int divisibleBy11(long int x);
main( )
{
long int num;
printf("Enter the number to be tested : ");
scanf("%ld", &num);
if(divisibleBy9(num))
printf("The number is divisible by 9\n");
else
printf("The number is not divisible by 9\n");
if(divisibleBy11(num))
printf("The number is divisible by 11\n");
else
printf("The number is not divisible by 11\n");
}/*End of main()*/
int divisibleBy9( long int n )
{
int sumofDigits;
	if(n==9)
	return 1;
	
	if(n<9)
	return 0;
	
	sumofDigits=0;
	
	while(n>0)
	{
	sumofDigits += n%10;
	n/=10;
	}
	
divisibleBy9(sumofDigits);

}/*End of divisibleBy9()*/

int divisibleBy11( long int n )
{
	int s1=0, s2=0,diff;
	if(n == 0)
		return 1;
	if(n < 10)
		return 0;
		
	while(n>0)
		{
		s1 += n%10;
		n /=10;
		s2 += n%10;
		n /= 10;
		}
		
diff = s1>s2 ? (s1-s2) : (s2-s1);
divisibleBy11(diff);

}/*End of divisibleBy11()*/

Output:

Enter the number to be tested : 99
The number is divisible by 9
The number is divisible by 11
Press any key to continue . . .

Explanation:

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