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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?

Problem statement

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

Counting digits of a number using recursion

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

C program to count digits of a number 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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