Question

Mark the following statements as true or false. a. To use a predefined function in a program, you need to know only the name of the function and how to use it. b. \(\mathrm{A}\) value-returning function returns only one value. c. Parameters allow you to use different values each time the function is called. When a return statement executes in a user-defined function, the function immediately exits. e. A value-returning function returns only integer values.

Short answer

a: True, b: True, c: True, d: True, e: False.

Step-by-step solution

Analyze Statement a

Statement a says, 'To use a predefined function in a program, you need to know only the name of the function and how to use it.' This statement is typically true, as knowing the name and usage pattern of a function is enough to implement it in a program.

Analyze Statement b

Statement b asserts, 'A value-returning function returns only one value.' This is generally true because a value-returning function is designed to return a single output upon execution.

Examine Statement c

Statement c posits, 'Parameters allow you to use different values each time the function is called.' This is true, as parameters are placeholders that enable you to pass different arguments, thereby changing the function's behavior or result on each call.

Evaluate the Return in User-defined Functions

Statement d states, 'When a return statement executes in a user-defined function, the function immediately exits.' This is true. Execution of a return statement concludes the function's processing and control is returned to the point from where the function was called.

Consider Statement e

Statement e claims, 'A value-returning function returns only integer values.' This is false, as a value-returning function can return any data type, not just integers. It can return floats, strings, objects, etc.

Key concepts

Predefined Functions

Predefined functions, also known as library functions, are built-in functions provided by a programming language, such as C++. These functions are pre-written and stored in libraries, ready to use in various programs. To incorporate a predefined function into your work, you simply need to know its name and understand how it functions. This eliminates the need to write common functions from scratch, saving time and reducing errors.

• Examples include mathematical functions like `sqrt()` for square roots or `pow()` for exponentiation.
• Knowing the syntax and the library that hosts the function is crucial; for C++, you typically include these libraries at the beginning of your code using `#include` directives.

Predefined functions are powerful tools but are limited to existing functionalities. Therefore, if unique processes are required, user-defined functions may be necessary.

Value-Returning Functions

Value-returning functions are designed to perform operations and return a single result to the caller. The primary aspect of these functions is that they provide a specific output value after execution, which can be used or stored for further processing.

• The declared type of a value-returning function dictates the type of the result it returns. For example, a function declared as `int` will return an integer.
• Functions like `max()` or `min()` often return values indicating the largest or smallest among inputs.

It's important to note that unlike what some might think, value-returning functions are not restricted to returning only integers. They can return floats, strings, or any defined complex types.

Function Parameters

Function parameters are essential in making functions dynamic and versatile. These are variables listed as part of a function's definition and are used to pass values or arguments into a function, allowing it to operate with different data each time it is called.
Function parameters enable developers to write reusable code. You can supply different inputs without changing the function's core logic.

• There are two main types:
  • Formal parameters: Defined in the function prototype, these are the placeholders for actual values.
  • Actual parameters: These are the real values passed to the function when it's called.
• Parameters make functions adaptable, as the same function can perform varied operations on different input sets.

Using parameters wisely can significantly enhance the flexibility and usability of your code.

User-Defined Functions

User-defined functions are specific functions that programmers create to perform particular tasks, which may not be efficiently handled by predefined functions. These functions help in organizing code better by dividing complex tasks into smaller, more manageable sub-tasks.

• A user-defined function typically begins with a definition that specifies its name, return type, and parameters.
• One key feature is the use of the `return` statement. When a `return` statement is encountered, it immediately stops the function's execution and sends the control back to the caller.

This ability to terminate executions promptly helps in exiting functions after achieving the required task, thus maintaining efficiency. User-defined functions are invaluable for implementing custom logic and handling tasks that require a specific order of operations.