# Sum algorithm in Java

The code below will find the sum of all elements in an array.

``````public int sum(int[] ray) {
int sum = 0;
for (int i = 0; i < ray.length; i++) {
sum += ray[i];
}
return sum;
}
``````

Let’s break down the pieces.

First, we’re creating a variable named `sum` to hold the sum of all the values in the array. We’re setting it to `0` because we haven’t found any values yet.

Then we loop through the array and add every element to `sum` so that at the end `sum` is holding the value of all elements added together.

And then we return.

Note that we used `sum += ray[i]` to add the values. We could have also used `sum = sum + ray[i]`. They’re the same thing.

## With a while loop

The same logic would work with a `while` loop.

``````public int sum(int[] ray) {
int sum = 0;
int i = 0;
while (i < ray.length) {
sum += ray[i];
i++;
}
return sum;
}
``````

## With a for each loop

And it would work with a for each loop as well.

``````public int sum(int[] ray) {
int sum = 0;
for (int i : ray) {
sum += i;
}
return sum;
}
``````

All three of these are doing the same thing. They’re starting with `0` and then adding every element of the array to it.

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