Java program to find the sum of all digits of a number :
In this tutorial, we will learn how to find the sum of all digits of a number in Java. Algorithm we are using is as below :
Algorithm :
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Start one infinite loop. This loop will run infinite times till user insert ‘-1’ as input.
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Take the number from the user as input.
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Declare one variable as ‘0’ to store the sum.
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Using one ’while’ loop, get the modulo 10 of the number and add it to the sum. If the number is 123, get ‘123%10’ i.e. 3 and add it to sum.
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Now, divide the number by 10 and set it as new value. i.e. for 123, set it to 123/10 = 12
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Do this till the number become_ ‘0’._
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Finally, Print out the result.
Example program :
import java.util.Scanner;
public class Main {
private static void println(String message) {
System.out.println(message);
}
public static void main(String[] args) throws java.lang.Exception {
Scanner sc = new Scanner(System.in);
while (true) {
println("");
println("Enter a number ( -1 to exit ): ");
int no = sc.nextInt();
if (no == -1) {
break;
}
int sum = 0;
while (no > 0) {
sum += no % 10;
no = no / 10;
}
println("Sum of all numbers is " + sum);
}
}
}
Example Output:
Enter a number ( -1 to exit ):
1
Sum of all numbers is 1
Enter a number ( -1 to exit ):
12
Sum of all numbers is 3
Enter a number ( -1 to exit ):
123
Sum of all numbers is 6
Enter a number ( -1 to exit ):
1234
Sum of all numbers is 10
Enter a number ( -1 to exit ):
12345
Sum of all numbers is 15
Enter a number ( -1 to exit ):
123456
Sum of all numbers is 21
Enter a number ( -1 to exit ):
-1
Process finished with exit code 0