Question

include using namespace std; void func1(); void func2(); int main() { int num; cout << "Enter 1 or 2: "; cin >> … # What is the output of the following program? #include using namespace std; void func1(); void func2(); int main() { int num; cout << "Enter 1 or 2: "; cin >> num; cout << endl; cout << "Take "; if (num == 1) func1(); else if (num == 2) func2(); else cout << "Invalid input. You must enter a 1 or 2" << endl; return 0; } void func1() { cout << "Programming I." <

Short answer

1: Take Programming I. 2: Take Programming II. 3 or -1: Invalid input.

Step-by-step solution

Analyze the Code Structure

The program first includes the iostream library and uses the standard namespace. It declares two void functions, `func1` and `func2`. Within `main`, it prompts the user to enter a number and initiates different actions depending on the value entered (1 or 2). It handles other entries as invalid.

Understand the Input and Output Manipulation

The program asks the user to enter a number. Depending on the input, it outputs different strings. If the input value is 1, it calls `func1()`, which prints "Programming I." If the input value is 2, it calls `func2()`, which prints "Programming II." For any other input, it prints "Invalid input. You must enter a 1 or 2." to the console.

Determine Output for Input 1

When the user inputs 1, the program prints "Take " followed by calling `func1()`, which adds "Programming I.". Therefore, the output is: ``` Take Programming I. ```

Determine Output for Input 2

When the user inputs 2, the program prints "Take " followed by calling `func2()`, which adds "Programming II.". Therefore, the output is: ``` Take Programming II. ```

Determine Output for Inputs Other Than 1 or 2

For any input other than 1 or 2, the program outputs a message indicating invalid input. For instance, if the input is 3 or -1, the output is: ``` Invalid input. You must enter a 1 or 2 ```

Recap Outputs for Specific Inputs

Let's summarize: - Input 1: "Take Programming I." - Input 2: "Take Programming II." - Input 3: "Invalid input. You must enter a 1 or 2" - Input -1: "Invalid input. You must enter a 1 or 2"

Key concepts

iostream library

In C++, the iostream library is used for input and output operations. It is essential because it grants access to the input/output streams used to receive data from the user and display it on the console. When you include the iostream library at the beginning of your program with `#include `, you get access to crucial components such as `cin` and `cout`.

- **`cout`**: This is used to output data to the console. In the program, `cout` is used to display prompts and messages like "Enter 1 or 2:" and "Take Programming I." - **`cin`**: This is utilized to take input from the user. In our code, it captures the user's input and stores it in a variable, typically for processing within the program.

By using `namespace std;`, you can avoid prefixing `cin` and `cout` with `std::`, making the code cleaner and easier to read.

function calls

Function calls are integral to breaking a program into smaller, manageable parts or modular units, each handling specific tasks. In C++, calling a function means executing the block of code defined in that function.

In the example code you provided: - The function `func1()` is called if the user enters `1`, and it prints "Programming I." to the console. - Similarly, the function `func2()` is called if the user enters `2`, and it prints "Programming II." to the console.
Calling a function involves writing the function's name followed by parentheses `()`; if the function has any parameters, you would include arguments inside the parentheses. However, in this example, func1 and func2 do not take any parameters.

user input handling

User input handling in C++ is vital for developing interactive applications that react to users' data input. In this process, the program fetches data entered by the user through the console using `cin`. This data can then be stored, processed, or evaluated as needed by your program.

In your sample code: - The program uses `cin >> num;` to capture a number inputted by the user and stores it in the variable `num`. - After the data is captured, it is evaluated using conditional statements to decide which function to call or whether to notify the user that their input was invalid.

Proper input handling ensures your program functions as expected even when a user provides incorrect or unexpected data, maintaining smooth and predictable user interactions.

void functions

Void functions in C++ are used when a function does not return a value. This type of function is declared with the keyword `void` before the function name. The primary purpose of void functions is to perform operations or actions, like printing text to the console, without expecting any return value at the end.

In the given program, both `func1()` and `func2()` are void functions: - **`func1()`**: Prints "Programming I." to the console. - **`func2()`**: Prints "Programming II." to the console.
Using void functions simplifies the program's flow by segmenting specific actions without concerning return values. This makes code organization clearer, especially when dealing with complex logic or repetitive tasks.