C++ User-Defined Functions and Parameters

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Questions and Answers

What is the primary characteristic of a user-defined function in C++?

It can only be used within the `main()` function.
It is defined by the programmer to perform a specific task. (correct)
It is a pre-built function provided by the C++ standard library.
It automatically executes at the start of the program.

Which of the following describes a 'void' function in C++?

A function that is used for exception handling.
A function that does not return any value. (correct)
A function that must return an integer value.
A function that can only accept integer parameters.

In C++, what is the purpose of a function prototype?

To call a function from within another function.
To declare a function without defining it, providing information to the compiler. (correct)
To define the actual code that the function will execute.
To specify the return type of the `main()` function.

Which of the following statements is true about built-in functions in C++?

They are part of the C++ language and available through libraries. (B)

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What happens to variables declared inside a function when the function finishes executing?

They are destroyed and their memory is deallocated. (A)

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In the following C++ code snippet, what does srand(time(0)) accomplish?

#include <iostream>
#include <cstdlib>
#include <ctime>

int main() {
    srand(time(0));
    int randomNumber = rand() % 100;
    return 0;
}

It seeds the random number generator with the current time. (D)

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Which of the following is a correct example of calling a user-defined function named `calculateSum` that takes two integer arguments?

int result = calculateSum(5, 10); (B)

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Which statement accurately describes the difference between arguments and parameters in a C++ function?

Parameters are variables in the function definition, while arguments are the actual values passed to the function. (B)

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Given the following function declaration, what is the correct way to call this function?

void printMessage(std::string message = "Hello");

printMessage(); (D)

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In C++, what is function overloading?

Defining multiple functions with the same name but different parameters. (A)

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Which of the following describes a function with no arguments and no return value?

It can perform an operation but cannot pass data in or out. (A)

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What is the purpose of the `return` statement in a C++ function?

To send a value back to the calling function. (A)

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When a function is called in C++, how does the program know where to return after the function is executed?

The return address is stored on the call stack before the function is called. (C)

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What happens if you declare a variable with the same name inside a function as a global variable?

The local variable shadows the global variable within the function's scope. (A)

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In C++, which of the following is NOT a valid reason for using functions?

To increase program execution speed. (B)

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Given the following C++ code:

#include <iostream>
int add(int a, int b) {
    int result = a + b;
    return result;
}
int main() {
    int x = 5, y = 7;
    add(x, y);
    return 0;
}

What is the issue with this code?

The result of <code>add(x, y)</code> is not stored or used. (B)

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What is a key benefit of using user-defined functions in C++?

They make code easier to understand and maintain. (A)

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In terms of function execution flow, what does it mean for a function to 'call' another function?

It means the current function temporarily pauses and executes another function before resuming. (B)

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Which of the following best describes the concept of 'code modularity' achieved through the use of functions?

Organizing code into independent, reusable blocks. (A)

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Consider the following C++ function definition:

int calculate(int x, int y = 10) {
    return x * y;
}

What will be the output of calculate(5)?

50 (D)

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In C++, what happens if you define two functions with the same name and the exact same parameter list?

The compiler will issue an error due to function redefinition. (C)

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What is the significance of the `cmath` library in C++ programming?

It provides functions for performing common mathematical operations. (B)

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Given the following code snippet, what is the output?

#include <iostream>
void myFunc(int x) {
    x = x + 10;
    std::cout << x << std::endl;
}
int main() {
    int y = 5;
    myFunc(y);
    std::cout << y << std::endl;
    return 0;
}

15\n5\n (D)

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Which of the following is a reason to use a function with arguments?

To allow the function to operate on different data each time it is called. (C)

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In C++, what is the purpose of the `cstdlib` library?

It contains functions for general utilities, such as random number generation, memory allocation, and environment control. (A)

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How does the use of function prototypes contribute to the compilation process in C++?

It helps the compiler check for correct function usage before the function is defined. (C)

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Given the following code, what does the function labs do?

#include <iostream>
#include <cstdlib>

int main() {
    long num = -70000;
    long absoluteValue = labs(num);
    std::cout << absoluteValue << std::endl;
    return 0;
}

Returns the absolute value of a long integer. (D)

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Consider this scenario: You need to create a function that calculates the area of a circle. Which of the following prototypes is the most appropriate?

float calculateArea(float radius); (B)

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What is the potential issue with the following C++ function?

int myFunction() {
    int result;
    return result;
}

The variable <code>result</code> is not initialized before being returned. (A)

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In C++, what is the purpose of the `exit()` function?

To terminate the entire program execution. (C)

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How do default arguments in C++ functions affect function overloading?

They can create ambiguity if overloaded functions can be called with the same arguments. (D)

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What is the primary difference between passing an argument 'by value' versus 'by reference' to a function?

Passing by value creates a copy of the argument, while passing by reference allows the function to modify the original argument. (D)

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Consider the following C++ code:

#include <iostream>

void modifyValue(int x) {
    x = 100;
}

int main() {
    int y = 50;
    modifyValue(y);
    std::cout << y << std::endl;
    return 0;
}

What value will be printed to the console?

50 (C)

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What is the main purpose of the `floor()` function in C++?

To round a number down to the nearest integer. (A)

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What does the term 'function signature' refer to in C++?

The combination of the function name, return type, and parameter list. (A)

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Consider the following C++ code:

#include <iostream>

int myFunc(int a, double b) {
    return a + b;
}

int main() {
    int x = 5;
    double y = 2.5;
    std::cout << myFunc(x, y) << std::endl;
    return 0;
}

What data type will be returned by myFunc in this code?

<code>int</code> (D)

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Which header file is required to use the `sqrt()` function in C++?

<code>cmath</code> (D)

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When should a function's return type be declared as `void`?

When the function does not need to return any value. (B)

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Flashcards

What is a function?

A block of code that runs when called.

What are functions?

Functions that may return a value, or perform actions, void functions don't return value.

What are built-in functions?

A function provided within C++ libraries.

What does sqrt() do?

Square root function in C++.

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What does abs() do in C++?

Integer absolute value function.

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What does fabs() do in C++?

Absolute value of double function.

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What does ceil() do?

Rounds a number UP to the nearest integer.

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What does floor() do?

Rounds a number DOWN to the nearest integer.

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What does exit() do?

Terminates the program.

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What does rand() do?

Generates a random number.

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What does srand() do?

Sets the seed for random number generation.

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What is user-defined function?

Function defined by the programmer.

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What is main() function?

Beginning of a C++ program execution.

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What is a function prototype?

Declaration of a function's return type, name, and parameters.

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What does it mean to call a function?

To start a user-defined function to run the function body code, the function needs to be called.

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What is a function definition?

The function's actual implementation.

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What is a function with no arguments?

Has no arguments and dont return a value.

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What are Void Functions?

Void functions are nonvalue-returning functions.

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What is a function with no arguments but a return value?

Has no arguments but do return a value.

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What is a local variable?

A variable existing only inside a function.

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What are parameters?

Values function receives when its called.

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What are arguments?

When a parameter is passed to the function.

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Passing arguments to function means..?

Refers to the data passed to the function when its called

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Return statement means..?

Returns a single value to the calling program.

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What are default arguments?

Arguments that have a default value specified in the function declaration.

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What is a function overloading?

Functions with the same name but different parameters

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Study Notes

Module 1 discusses user-defined functions and parameters in C++.
Lesson 1 focuses on user-defined functions
Lesson 2 will discuss function parameters
C++ is used throughout

Objectives

At the end of this subtopic, the goal is to identify types and create user-defined functions in C++.

Functions Overview

Functions are procedures, subprograms, and methods
Functions are blocks of code
Functions only run when called
Two types of functions:
- Built-in
- User-defined
Functions may return a value or perform an action without returning a value
Functions not returning a value are void functions

Built-in Functions

C++ provides libraries of predefined functions.
sqrt(): Calculates the square root of a number; takes a double and returns a double. (ex: sqrt(4.0) = 2.0)
pow(): Raises a number to a power; takes two doubles and returns a double. (ex: pow(2.0,3.0) = 8.0)
abs(): Returns the absolute value of an integer; takes an integer and returns an integer. (ex: abs(-7) = 7)
labs(): Returns the absolute value of a long integer; takes a long and returns a long (ex: labs(-70000) = 70000)
fabs(): Returns the absolute value of a double; takes a double and returns a double. (ex: fabs(-7.5) = 7.5)
ceil(): Rounds a number upwards to the nearest integer; takes a double and returns a double. (ex: ceil(3.2) = 4.0)
floor(): Rounds a number downwards to the nearest integer; takes a double and returns a double. (ex: floor(3.2) = 3.0)
exit(): Ends program execution; takes an integer and returns void
rand(): Generates a random number; takes None and returns an int
srand(): Seeds the random number generator; takes an unsigned int and returns void

User-Defined Functions

They are defined by the programmer
A user-defined function groups code to perform a specific task
The group of code is named with an identifier
Invoking the function calls executes the defined code in the body of the function

How User-Defined Functions Work

When running a program, the system calls the main() function and executes the code within
When program control reaches a function name in main(), it moves to that function
It executes the code within the function
Once the function is complete, control returns to the main() function
It continues with the code after the function call.

User-Defined Function Example

Code can be written to add integers and display the sum using user defined functions such as add()

Function Prototype (Declaration)

In C++, a function prototype declares a function without its body
In C++, the prototype informs the compiler about a user-defined function

Function Call

Function can be called to execute its body
Example: add(num1, num2) inside main() calls the user-defined function
The function returns an integer in variable add.

Function Definition

The 'function definition' refers to the actual function: int add(int a, int b) { int add; add = a + b; return add; }

Types of User-Defined Functions

Function with no argument and no return value
Function with no argument but return value
Function with argument but no return value
Function with argument and return value

Void Functions

Void functions accomplish tasks and return control to the caller
Void functions are also called nonvalue-returning functions
The void function call is a stand-alone statement

Function with No Argument/Return Value Example

The prime() function is called from main() without arguments
The prime() function takes a number from the user
It checks if the number is prime without returning a value
The return type of the prime() function is void

No Arguments Passed, but a Return Value

Return type of the prime() function is an int
The function returns the inputted number from the user back to the main() function

Local Variables

A variable declared inside a function is called a 'local variable'
It only exists locally within the function
The local variables are no longer available when the function returns

Parameters and Arguments

Information can be passed via a parameter
Parameters are specified after the function name and within parentheses
Parameters act as variables inside the function
When a parameter is passed to the function, it is an argument
A 'parameter' is a variable in a method definition
The 'arguments' are the data passed to the parameter
The parameter is a variable that acts as a place holder for the argument

Passing Arguments to a Function

Arguments refer to the data is that passed to a function when called

Return Statement

A function can return a single value using the return statement.

Default Arguments in Functions

Can write code to demonstrate use of default arguments

Arguments Passed, but No Return Value

Code passes arguments to prime()
The program checks if that number is a prime, and prints without a return

Arguments Passed, With a Return Value

The user is asked for a positive number
The prime() function runs whether the input number is a prime
The return type of prime() is an int, the main() function returns
The main() returns "1" if number is prime
The main() returns "0" if is not prime

Function Overloading

The function has the same name but differing arguments
Functions of different number or type of parameters,
Example: int test() { } int test(int a) { } float test(double a) { } int test(int a, double b) { }
The program calls the display() function three times
Function overloading uses different types or numbers of arguments
The return type are that same, but that is not necessary

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C++ User-Defined Functions and Parameters

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Questions and Answers

What is the primary characteristic of a user-defined function in C++?

Which of the following describes a 'void' function in C++?

In C++, what is the purpose of a function prototype?

Which of the following statements is true about built-in functions in C++?

What happens to variables declared inside a function when the function finishes executing?

In the following C++ code snippet, what does srand(time(0)) accomplish? #include <iostream> #include <cstdlib> #include <ctime> int main() { srand(time(0)); int randomNumber = rand() % 100; return 0; }

Which of the following is a correct example of calling a user-defined function named calculateSum that takes two integer arguments?

Which statement accurately describes the difference between arguments and parameters in a C++ function?

Given the following function declaration, what is the correct way to call this function? void printMessage(std::string message = "Hello");

In C++, what is function overloading?

Which of the following describes a function with no arguments and no return value?

What is the purpose of the return statement in a C++ function?

When a function is called in C++, how does the program know where to return after the function is executed?

What happens if you declare a variable with the same name inside a function as a global variable?

In C++, which of the following is NOT a valid reason for using functions?

Given the following C++ code: #include <iostream> int add(int a, int b) { int result = a + b; return result; } int main() { int x = 5, y = 7; add(x, y); return 0; } What is the issue with this code?

What is a key benefit of using user-defined functions in C++?

In terms of function execution flow, what does it mean for a function to 'call' another function?

Which of the following best describes the concept of 'code modularity' achieved through the use of functions?

Consider the following C++ function definition: int calculate(int x, int y = 10) { return x * y; } What will be the output of calculate(5)?

In C++, what happens if you define two functions with the same name and the exact same parameter list?

What is the significance of the cmath library in C++ programming?

Given the following code snippet, what is the output? #include <iostream> void myFunc(int x) { x = x + 10; std::cout << x << std::endl; } int main() { int y = 5; myFunc(y); std::cout << y << std::endl; return 0; }

Which of the following is a reason to use a function with arguments?

In C++, what is the purpose of the cstdlib library?

How does the use of function prototypes contribute to the compilation process in C++?

Given the following code, what does the function labs do? #include <iostream> #include <cstdlib> int main() { long num = -70000; long absoluteValue = labs(num); std::cout << absoluteValue << std::endl; return 0; }

Consider this scenario: You need to create a function that calculates the area of a circle. Which of the following prototypes is the most appropriate?

What is the potential issue with the following C++ function? int myFunction() { int result; return result; }

In C++, what is the purpose of the exit() function?

How do default arguments in C++ functions affect function overloading?

What is the primary difference between passing an argument 'by value' versus 'by reference' to a function?

Consider the following C++ code: #include <iostream> void modifyValue(int x) { x = 100; } int main() { int y = 50; modifyValue(y); std::cout << y << std::endl; return 0; } What value will be printed to the console?

What is the main purpose of the floor() function in C++?

What does the term 'function signature' refer to in C++?

Consider the following C++ code: #include <iostream> int myFunc(int a, double b) { return a + b; } int main() { int x = 5; double y = 2.5; std::cout << myFunc(x, y) << std::endl; return 0; } What data type will be returned by myFunc in this code?

Which header file is required to use the sqrt() function in C++?

When should a function's return type be declared as void?

Flashcards

What is a function?

What are functions?

What are built-in functions?

What does sqrt() do?

What does abs() do in C++?

What does fabs() do in C++?

What does ceil() do?

What does floor() do?

What does exit() do?

What does rand() do?

What does srand() do?

What is user-defined function?

What is main() function?

What is a function prototype?

What does it mean to call a function?

What is a function definition?

What is a function with no arguments?

What are Void Functions?

What is a function with no arguments but a return value?

What is a local variable?

What are parameters?

What are arguments?

Passing arguments to function means..?

Return statement means..?

What are default arguments?

What is a function overloading?

Study Notes

Objectives

Functions Overview

Built-in Functions

User-Defined Functions

How User-Defined Functions Work

User-Defined Function Example

Function Prototype (Declaration)

Function Call

Function Definition

Types of User-Defined Functions

In the following C++ code snippet, what does `srand(time(0))` accomplish?

`#include <iostream> #include <cstdlib> #include <ctime> int main() { srand(time(0)); int randomNumber = rand() % 100; return 0; }`

Which of the following is a correct example of calling a user-defined function named `calculateSum` that takes two integer arguments?

Given the following function declaration, what is the correct way to call this function?

`void printMessage(std::string message = "Hello");`

What is the purpose of the `return` statement in a C++ function?

Given the following C++ code:

`#include <iostream> int add(int a, int b) { int result = a + b; return result; } int main() { int x = 5, y = 7; add(x, y); return 0; }`

What is the issue with this code?

Consider the following C++ function definition:

`int calculate(int x, int y = 10) { return x * y; }`

What will be the output of `calculate(5)`?

What is the significance of the `cmath` library in C++ programming?

Given the following code snippet, what is the output?

`#include <iostream> void myFunc(int x) { x = x + 10; std::cout << x << std::endl; } int main() { int y = 5; myFunc(y); std::cout << y << std::endl; return 0; }`

In C++, what is the purpose of the `cstdlib` library?

Given the following code, what does the function labs do?

`#include <iostream> #include <cstdlib> int main() { long num = -70000; long absoluteValue = labs(num); std::cout << absoluteValue << std::endl; return 0; }`

What is the potential issue with the following C++ function?

`int myFunction() { int result; return result; }`

In C++, what is the purpose of the `exit()` function?

Consider the following C++ code:

`#include <iostream> void modifyValue(int x) { x = 100; } int main() { int y = 50; modifyValue(y); std::cout << y << std::endl; return 0; }`

What value will be printed to the console?

What is the main purpose of the `floor()` function in C++?

Consider the following C++ code:

`#include <iostream> int myFunc(int a, double b) { return a + b; } int main() { int x = 5; double y = 2.5; std::cout << myFunc(x, y) << std::endl; return 0; }`

What data type will be returned by `myFunc` in this code?

Which header file is required to use the `sqrt()` function in C++?

When should a function's return type be declared as `void`?