In this blog post, you will see how to Find the sum of digits in a string using Java. A string can have any characters. Here we will find the digit characters in a given string and calculate their sum.
Procedure to calculate the sum of digits in a String:
- Declare and Initialize a String variable.
- Declare a sum variable to hold the sum of digits.
- Use the
charAt()method to extract a single character from a given String. - Now use the
isDigit()method to check character is a digit or not, if yes add it to the sum variable else ignore it. - Before adding the digit to the sum, convert it to an integer from a character using
getNumericValue()method ofCharacterclass. - Repeat the 3 to 5 steps until the end of the String.
- Finally, print the total sum.
Let’s see a few examples for it below:
Example-1. Calculate the sum of all numbers in a string in Java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 | package com.javacodepoint.string;public class SumOfDigitInString { // Method to calculate sum of digits public static int sumOfDigitInString(String str) { // initialize sum variable int sum = 0; for (int i = 0; i < str.length(); i++) { // extract single character from string char ch = str.charAt(i); // check digit character if (Character.isDigit(ch)) { // convert character to digit and add into sum variable int digit = Character.getNumericValue(ch); sum = sum + digit; } } // finally return the calculated sum return sum; } // Main method public static void main(String[] args) { // Declare and Initialize a string (with digits) String stringWithDigit = "1ab26xyz88www5"; // Find the sum int sum = sumOfDigitInString(stringWithDigit); // Print the result System.out.println("The sum of total available digits in the given String= " + sum); }} |
OUTPUT:
The sum of total available digits in the given String= 30
Example-2. Sum of digits in a String in Java using Scanner
In this example, we will take string input from the user using java.lang.Scanner class. The next() method of the Scanner class is used to read a string from the user input device. let’s see the java program below:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | package com.javacodepoint.string;import java.util.Scanner;public class SumOfDigitInString2 { // Method to calculate sum of digits public static int sumOfDigitInString(String str) { // initialize sum variable int sum = 0; for (int i = 0; i < str.length(); i++) { // extract single character from string char ch = str.charAt(i); // check digit character if (Character.isDigit(ch)) { // convert character to digit and add into sum variable int digit = Character.getNumericValue(ch); sum = sum + digit; } } // finally return the calculated sum return sum; } // Main method public static void main(String[] args) { // Scanner object to read user input Scanner sc = new Scanner(System.in); System.out.println("Enter a string with digit characters: "); String stringWithDigit = sc.next(); // Find the sum int sum = sumOfDigitInString(stringWithDigit); // Print the result System.out.println("The sum of total available digits in the given String= " + sum); }} |
OUTPUT:
Enter a string with digit characters:
java12345codepoint
The sum of total available digits in the given String= 15
See also:
Java Program to Count the Number of Vowels in a String.
Java Program to Count characters from the string in Java.