Java Program to Count Number of Digits in a Number

Write a Java program to count number of digits in a number. In this program, We take a number as an input and print the count of digit in a number.

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Java Program to Count Number of Digits in a Number

import java.util.*;

public class CountDigit {

    
    public static void main(String[] args) {
        
        int num, count = 0;
        
        System.out.println("Enter a number");
        Scanner in = new Scanner(System.in);
        
        num = in.nextInt();
        
        while( num > 0) {
            
            //Reduce number in each iteration
            num = num / 10;
            
            //count
            count++;
        }
        
        System.out.println("Number of digits in a number 
                            is "+ count);
    }
    
}

Output :

Enter a number  - 356

Number of digits in a number is - 3


Let's understand how this program works-

Iteration 1 - Our input number is 356

In first iteration, value of num variable is 356.

num = num / 10 = 35
count = 1

Iteration 2

After first iteration, value of num variable is 35.

num = num / 10 = 3
count = 2

Iteration 3

After second iteration, value of num variable is 3.

num = num / 10 = 0
count = 3


After third iteration our while loop terminate, As it not satisfy the condition (num is greater than zero). So our program will print number of digits in a number is 3.