1) Write a Rust function that accepts two Strings (or string slices) as input, and returns the concatenation of the two.

2) Write a Rust function that accepts an array of floating point values, and a tuple containing an upper and lower bound. Return the average of the values in the slice defined by the upper and lower bounds. Assume the tuple contains valid bounds. No need to error check.

3) Write a Rust signum function. It should accept an array of integers, and change the elements in the array values to -1, 0, or 1 depending on the sign of the elements in the argument array. Hint: Youre not returning a new array, youre changing the original.