8.2.1: Function Pass by Reference - Transforming Coordinates Define a function `CoordTransform()` that transforms its first two input parameters, `xVal` and `yVal`, into two new output parameters, `xValNew` and `yValNew`. The function should return `void`. The transformation is new.

To create a function named `CoordTransform()` that takes `xVal` and `yVal` as input parameters by reference and transforms them into `xValNew` and `yValNew`, you need to specify the parameters as reference parameters. In C++, this is signified by the ampersand symbol (`&`) placed before the parameter name. Here's how you can define the function:

```cpp void CoordTransform(double &xVal, double &yVal) { // Here, implement the transformation logic // For example, if we simply want to swap the values, we could do: double temp = xVal; xVal = yVal; yVal = temp;

// After this, xValNew and yValNew aren't used, because xVal and yVal themselves // have been updated by reference. This means that the original variables passed // to the function will now contain the new transformed values. } ```

When calling this function, you would do so using actual variables for `xVal` and `yVal`. After the function is called, the values of these variables will have been transformed according to the logic inside `CoordTransform()`.

Remember that the function returns `void`, which means it does not return any value. Instead, it directly modifies the input parameters because they are passed by reference.

Extra: When a function parameter is passed by reference, it means that the function receives a reference to the original memory location of the argument, not just a copy of its value. This allows the function to modify the original variable. In contrast, passing by value would create a copy of the variable's data, and modifications in the function would not affect the original variable.

Passing by reference is very useful when you want a function to modify its arguments, or when you want to avoid the overhead of copying large amounts of data for performance reasons. However, one must use caution as it can lead to side effects if the modifications to the parameters are not intentional or well-documented.