Here is a 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.
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;
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;
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 (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
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