Module 1 Introduction to Cpp

Writing Your First C++ Program: Hello, World!

Program Code:

cpp

#include <iostream> // Include the input-output stream library

int main() {

std::cout << “Hello, World!” << std::endl; // Output “Hello, World!” to the console

return 0; // Indicate that the program ended successfully

}

Explanation:

#include <iostream>: This is a preprocessor directive that includes the input-output stream library, which is necessary for using std::cout.
int main(): This is the main function where the execution of the program begins.
std::cout: This is used to print output to the console.
“Hello, World!”: The message to be displayed.
std::endl: This inserts a new line and flushes the output buffer.
return 0;: This signifies that the program has executed successfully.

Steps to Run the Program:

1. Using Visual Studio (Windows)

Open Visual Studio: Launch the IDE and create a new Console App project.
Write the Code: Replace the default code with the “Hello, World!” program.
Build and Run: Press Ctrl + F5to build and run the program. You should see “Hello, World!” in the console.

2. Using Code::Blocks (Cross-platform)

Open Code::Blocks: Start the IDE and create a new Console Application project.
Write the Code: Enter the “Hello, World!” code in the editor.
Build and Run: Click on “Build and Run” (or press F9). The output will display in the console.

3. Using CLion (Cross-platform)

Open CLion: Start the IDE and create a new project.
Write the Code: Replace the main file content with the “Hello, World!” program.
Build and Run: Click on “Run” or press Shift + F10to compile and execute the program.

4. Using Xcode (macOS)

Open Xcode: Create a new Command Line Tool project.
Write the Code: Paste the “Hello, World!” code in the main file.
Build and Run: Click the play button to build and run the program. The output will appear in the debug console.

5. Using Visual Studio Code (Cross-platform)

Open VS Code: Create a new file and save it as cpp.
Write the Code: Enter the “Hello, World!” code in the file.
Compile: Open the terminal and run g++ -o hello hello.cppto compile the code.
Run: Execute the compiled file with ./hello(Linux/macOS) or exe (Windows). You will see “Hello, World!” printed in the terminal.

Basic Syntax and Structure

Understanding the syntax and structure of C++ is essential for writing clear and efficient programs. Here’s a breakdown of the key components:

1. Structure of a C++ Program

A typical C++ program consists of the following parts:

cpp

#include <iostream> // Preprocessor directive for input-output operations

int main() {

std::cout << “Hello, World!” << std::endl; // Output statement

return 0; // Return statement indicating successful execution

}

Explanation:

Preprocessor Directives: Lines starting with #(e.g., #include <iostream>) are preprocessor commands. They instruct the compiler to include necessary libraries.
Main Function: int main()is the entry point of a C++ program. The code inside main is executed first.
Statements: Each statement ends with a semicolon (;).
Return Statement: return 0;signifies the program ended successfully.

2. Basic Syntax Elements

Comments:
- Single-line comment: // This is a comment
- Multi-line comment: /* This is a multi-line comment */

Variables: Variables are used to store data.

cpp

int number = 10; // Declares an integer variable

Data Types: Common data types include:
- int(integer)
- float(floating-point)
- char(character)
- bool(boolean)
- string(requires #include <string>)
Input and Output:
- Output: std::cout << “Text”;

Input:

cpp

int age;

std::cin >> age; // Reads input into the variable age

3. Control Structures

Control the flow of the program using conditions and loops.

If-Else:

cpp

if (condition) {

// Code if condition is true

} else {

// Code if condition is false

}

For Loop:

cpp

for (int i = 0; i < 5; i++) {

std::cout << i << std::endl;

}

While Loop:

cpp

while (condition) {

// Code while condition is true

}

4. Functions

Functions allow code reuse and modular programming.

cpp

CopyEdit

int add(int a, int b) {

return a + b;

}

int main() {

int sum = add(5, 3);

std::cout << “Sum: ” << sum << std::endl;

return 0;

}

Function Components:

Return Type: Specifies the type of value the function returns.
Function Name: Identifier for the function.
Parameters: Variables that the function accepts.
Body: The code inside {}defining what the function does.

Tag: Module 1 Introduction to Cpp