Write the C++ code for a function that receives four double numbers. The function should calculate the average of the four numbers and then return the result. Name the function calc Average. Name the formal parameters num1, num2, num3, and num4. Also write an appropriate function prototype for the calc Average function. In addition, write a statement that invokes the calc Average function and assigns its return value to a double variable named quotient. Use the following numbers as the actual arguments: 45.67, 8.35, 125.78, and 99.56.