- Java program to find the count of digits in a number using loop and logarithm.

In this java program, we have to find the number of digits in given integer.

For Example:

Count of digits in 1435238 is 7

## Java program to find the count of digits in an integer

In this program, we count the number of digits in N by removing one digit from N at a time in every iteration and increment count until N becomes zero.

**Algorithm to count digits of a number**

Let N be the given number and "count" be an integer variable for storing number of digits in N.

- Initialize count to 0.
- Remove the least significant digit from N. (N = N /10;)
- Increment count.
- Repeat above two steps, till N is not equal to zero.

package com.tcc.java.programs; import java.util.Scanner; /** * Java Program to count digits in a number */ public class CountDigits { public static void main(String[] args) { int number, count = 0, temp; Scanner scanner; scanner = new Scanner(System.in); System.out.println("Enter an Integer"); number = scanner.nextInt(); temp = number; while (temp != 0) { temp = temp / 10; ++count; } System.out.format("Number of Digits in %d = %d", number, count); } }Output

Enter an Integer 63542 Number of Digits in 63542 = 5

Enter an Integer 1 Number of Digits in 1 = 1

## Java program for counting digits of a number using logarithm

We first take a number N as input from user and check if it is a negative number. If true, then we multiply it by -1 to make it positive.
Here we are using log10(logarithm of base 10) to count the number of digits of N (logarithm is not defined for negative numbers).

Digit count of N = log10(N) + 1

package com.tcc.java.programs; import java.util.Scanner; /** * Java Program to count digits in a number using logarithm */ public class CountDigitsLog { public static void main(String[] args) { int number, count = 0, temp; Scanner scanner; scanner = new Scanner(System.in); System.out.println("Enter an Integer"); number = scanner.nextInt(); temp = number; /* If input number is negative then make it positive */ if (temp < 0) temp = temp * -1; if (temp != 0) { /* If input number is non-zero */ count = (int) Math.log10(temp) + 1; } else { count = 1; } System.out.format("Number of Digits in %d = %d", number, count); } }Output

Enter an Integer 1234 Number of Digits in 1234 = 4

Enter an Integer 1 Number of Digits in 1 = 1