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Solution Review: Count the Digits in a Number Using Recursion

Explore how to use recursion in C++ to count the digits in an integer. This lesson guides you through writing a recursive function that divides the number by 10 each call until only one digit remains. You will understand the base case and recursive logic needed to solve this problem effectively.

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Solution

Press the RUN button and see the output!

C++
#include <iostream>
using namespace std;
// Recursive count_digits function
int count_digits(int number) {
  // Base Case
  if (abs(number)/10 == 0) {
    return 1;
  }
  // Recursive Case  
  else {
    return 1 + count_digits(number / 10);
  }
}
// main function
int main() {
  // Initialize number
  int number = 8625;
  // Declare variable result
  int result;
  // Call count_digits function in main and store the returned value in result
  result = count_digits(number);
  // Print value of result
  cout << "Number of digits = " << result;
  return 0;
}

Explanation

count_digits function

The recursive ...