Question

(This exercise is for those who have studied the optional section on default arguments.) What output does the following function provide in response to the following calls? void func (double \(x,\) double \(y=1.1,\) double \(z=2.3\) ) \\{ cout \(<

Short answer

Answer: The output for the given calls are as follows: a. "2.0 1.1 2.3" b. "2.0 3.0 2.3" c. "2.0 3.0 4.0"

Step-by-step solution

Call A: func(2.0)

In this call, only one value is provided: x = 2.0. Since we do not provide values for y and z, their default values will be used: y = 1.1 and z = 2.3. The function will then output: "2.0 1.1 2.3".

Call B: func(2.0, 3.0)

In this call, two values are provided: x = 2.0 and y = 3.0. We do not provide a value for z, so its default value will be used: z = 2.3. The function will then output: "2.0 3.0 2.3".

Call C: func(2.0, 3.0, 4.0)

In this call, all three values are provided: x = 2.0, y = 3.0, and z = 4.0. No default values will be used since all arguments have corresponding input values. The function will then output: "2.0 3.0 4.0". So the output provided in response to the given calls is as follows: a. "2.0 1.1 2.3" b. "2.0 3.0 2.3" c. "2.0 3.0 4.0"

Key concepts

Function Overloading

Function overloading in C++ programming is a feature that allows us to have more than one function with the same name in the same scope, but with different parameters. This comes in very handy when you need to perform similar operations that require a different number or types of parameters.

For instance, let's consider a simple function add() that adds two numbers. With overloading, we can create another function add() that takes three numbers instead of two and adds them. The compiler differentiates these functions by their parameter list (including the number, types, and order of parameters).

Let's connect this to our exercise. You might think of the default arguments as a form of overloading. While it is not traditional overloading, because there's only one actual function definition, default arguments allow us to call the same function with different numbers of parameters. It's a convenient alternative to defining multiple overloaded functions when the operations are essentially the same and only some parameters change.

Parameter Passing

Parameter passing is a fundamental concept where we provide inputs to functions when we call them. In C++, parameters can be passed by value or by reference. Passing by value means that the function receives a copy of the actual parameter, so any modifications inside the function do not affect the original argument. Conversely, passing by reference means that the function can modify the original argument. Now, onto our example, parameter passing with default arguments introduces efficiency and flexibility.

When we call func(2.0), only one parameter is passed, and C++ fills in the rest with default values. For func(2.0, 3.0), the first two parameters are passed by value, and the default is used for the third. But what if we wanted to skip y and only provide x and z? In C++, this isn't directly possible because default parameters can only be omitted from right to left. Therefore, if a default value for a parameter is to be used, all subsequent parameters in the list must also have default values.

C++ Programming Fundamentals

Understanding the basics of C++ lays a solid foundation for both new and seasoned programmers to build complex applications. One of the essentials in C++ is knowing how functions work, including declaration, definition, and invocation. Functions allow for code reuse and organization, making programs easier to read and maintain.

In the provided exercise, the function func() is defined with default arguments, which showcases another C++ fundamental: default arguments provide values for function parameters that can be omitted when the function is called. It's crucial to remember the signature of a function includes the function name and its parameter types; however, default values are not part of the function's signature.

In conclusion, these C++ programming fundamentals not only make the language versatile but also give programmers powerful tools to write efficient and readable code. These staples are often covered in introductory C++ courses and textbooks, fostering a deeper understanding of how the language operates under various scenarios, such as the one presented in our exercise.