# return the sum of an array

## Returning the Sum of an Array

If you have an array of numbers and you want to find the sum of all the numbers in the array, there are a couple of ways to accomplish this. One way is to use a for loop to iterate through the array and add up each number:

```
function sumArray(arr) {
var sum = 0;
for (var i = 0; i < arr.length; i++) {
sum += arr[i];
}
return sum;
}
var myArray = [1, 2, 3, 4, 5];
var mySum = sumArray(myArray);
console.log(mySum);
```

In this code, we define a function called `sumArray`

that takes an array as its argument. We then create a variable called `sum`

and set it to 0. We use a for loop to iterate through each number in the array and add it to the `sum`

variable. Finally, we return the `sum`

variable.

To use this function, we create an array called `myArray`

containing the numbers 1 through 5. We then call the `sumArray`

function and pass in `myArray`

as its argument. The result is stored in a variable called `mySum`

, which we then log to the console.

Another way to find the sum of an array is to use the `reduce`

method:

```
function sumArray(arr) {
var sum = arr.reduce(function(a, b) {
return a + b;
}, 0);
return sum;
}
var myArray = [1, 2, 3, 4, 5];
var mySum = sumArray(myArray);
console.log(mySum);
```

In this code, we define the `sumArray`

function again. This time, we use the `reduce`

method to iterate through the array and add up each number. The `reduce`

method takes a function as its argument that is used to accumulate the result. In this case, the function takes two arguments, `a`

and `b`

, which represent the accumulated result and the current element of the array. The function returns the sum of `a`

and `b`

. We also pass in a second argument to `reduce`

, which is the initial value of the accumulated result (in this case, 0). Finally, we return the result of the `reduce`

method.

To use this function, we create an array called `myArray`

containing the numbers 1 through 5. We then call the `sumArray`

function and pass in `myArray`

as its argument. The result is stored in a variable called `mySum`

, which we then log to the console.