In this challenge, you will practice using the for loop in Rust to iterate over a range of numbers. The goal is to sum all the even numbers within a given range.

The for loop in Rust is a powerful construct that allows you to iterate over collections, ranges, and iterators. It is commonly used for tasks such as summing numbers, collecting items, and more. By utilizing the for loop, you can write concise and readable code to perform repetitive tasks.

Your task is to implement a function sum_of_evens that takes two arguments, start and end, both of which are i32. The function should return the sum of all even numbers within the range [start, end] inclusive. If start is greater than end, the function should return 0.

• Use a for loop to iterate over the range from start to end.
• Sum only the even numbers within the specified range.
• If start is greater than end, return 0.

let result = sum_of_evens(1, 10);
assert_eq!(result, 30); // 2 + 4 + 6 + 8 + 10 = 30
 
let result = sum_of_evens(5, 5);
assert_eq!(result, 0); // 5 is not even
 
let result = sum_of_evens(10, 1);
assert_eq!(result, 0); // start is greater than end