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
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:
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.