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C program to count digits of a number using recursion

In this C program, we are going to learn how to count total number of digits of a number using recursion?

Given an integer number and we have to count the digits using recursion using C program.

In this program, we are reading an integer number and counting the total digits, here countDigits() is a recursion function which is taking number as an argument and returning the count after recursion process.

Example:

    Input number: 123
    Output:
    Total digits are: 3

Program to count digits in C using recursion

/*C program to count digits using recursion.*/
 
#include <stdio.h>
 
//function to count digits
int countDigits(int num)
{
    static int count=0;
     
    if(num>0)
    {
        count++;
        countDigits(num/10);
    }
    else
    {
        return count;
    }
}
int main()
{
    int number;
    int count=0;
     
    printf("Enter a positive integer number: ");
    scanf("%d",&number);
     
    count=countDigits(number);
     
    printf("Total digits in number %d is: %d\n",number,count);
     
    return 0;
}

Output

Enter a positive integer number: 123
Total digits in number 123 is: 3 

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