Java method to sum any number of ints

Question

I need to write a java method sumAll() which takes any number of integers and returns their sum.

sumAll(1,2,3) returns 6
sumAll() returns 0
sumAll(20) returns 20

I don't know how to do this.

Answer 1

You need:

public int sumAll(int...numbers){

    int result = 0;
    for(int i = 0 ; i < numbers.length; i++) {
        result += numbers[i];
    } 
    return result;
}

Then call the method and give it as many int values as you need:

int result = sumAll(1,4,6,3,5,393,4,5);//.....
System.out.println(result);

Answer 2

If your using Java8 you can use the IntStream:

int[] listOfNumbers = {5,4,13,7,7,8,9,10,5,92,11,3,4,2,1};
System.out.println(IntStream.of(listOfNumbers).sum());

Results: 181

Just 1 line of code which will sum the array.

Answer 3

public int sumAll(int... nums) { //var-args to let the caller pass an arbitrary number of int
    int sum = 0; //start with 0
    for(int n : nums) { //this won't execute if no argument is passed
        sum += n; // this will repeat for all the arguments
    }
    return sum; //return the sum
}