Arrays are a fundamental data structure in Rust that allow you to store a fixed-size collection of elements of the same type. A common operation is to calculate the sum of all elements in an array.

In this challenge, you will implement a function to calculate the sum of elements in an array of integers i32.

Your task

You need to implement the function sum_array(arr: &[i32]) -> i32 that takes a slice of integers and returns the sum of all elements.

Requirements

• The sum_array function should return the sum of all elements in the array.

Example

let arr = [1, 2, 3, 4, 5];

let sum = sum_array(&arr);
assert_eq!(sum, 15); // 1 + 2 + 3 + 4 + 5 = 15

Hints

• Use the .iter() method to iterate over the elements of the array.
• Use the .sum() method to calculate the sum of the elements.