Environment Setup and First Program¶

1. What is C++?¶

C++ is a general-purpose programming language developed by Bjarne Stroustrup in 1979, extending the C language.

Features of C++¶

Feature	Description
Object-Oriented	Supports classes, inheritance, polymorphism
High Performance	Low-level control close to hardware
Multi-Paradigm	Procedural, object-oriented, functional programming
Compatibility	Mostly compatible with C code
STL	Powerful Standard Template Library

C++ Version History¶

C++98 ──▶ C++03 ──▶ C++11 ──▶ C++14 ──▶ C++17 ──▶ C++20 ──▶ C++23
 │                     │
 │                     └── Beginning of "Modern C++"
 └── First standard

2. Development Environment Installation¶

Windows¶

Method 1: MinGW-w64 (Recommended)

Install MSYS2
Run in MSYS2 terminal: bash pacman -S mingw-w64-ucrt-x86_64-gcc
Add to PATH environment variable: C:\msys64\ucrt64\bin

Method 2: Visual Studio

Install Visual Studio Community
Select "Desktop development with C++" workload

macOS¶

# Install Xcode Command Line Tools
xcode-select --install

# Or install GCC via Homebrew
brew install gcc

Linux (Ubuntu/Debian)¶

# Install GCC
sudo apt update
sudo apt install g++ build-essential

# Check version
g++ --version

Linux (CentOS/RHEL)¶

# Install GCC
sudo dnf install gcc-c++

# Check version
g++ --version

3. First Program: Hello World¶

Writing Code¶

Create a hello.cpp file:

#include <iostream>

int main() {
    std::cout << "Hello, World!" << std::endl;
    return 0;
}

Code Explanation¶

#include <iostream>    // Include I/O library
                       // <> means standard library

int main() {           // Program entry point
                       // int is return type

    std::cout          // Standard output (console)
              << "Hello, World!"  // Send string via output operator
              << std::endl;       // Newline + flush buffer

    return 0;          // Return 0 = normal termination
}

Compile and Run¶

# Compile
g++ hello.cpp -o hello

# Run
./hello      # Linux/macOS
hello.exe    # Windows

Output:

Hello, World!

Compiler Options¶

Option	Description
`-o filename`	Specify output file name
`-std=c++17`	Specify C++ standard version
`-Wall`	Enable all warnings
`-Wextra`	Enable extra warnings
`-g`	Include debugging information

# Recommended compile command
g++ -std=c++17 -Wall -Wextra hello.cpp -o hello

4. Basic Input/Output¶

Output: std::cout¶

#include <iostream>

int main() {
    // String output
    std::cout << "Hello" << std::endl;

    // Multiple values
    std::cout << "Number: " << 42 << std::endl;

    // Multiple lines
    std::cout << "Line 1\n"
              << "Line 2\n"
              << "Line 3" << std::endl;

    return 0;
}

Input: std::cin¶

#include <iostream>

int main() {
    int age;
    std::cout << "Enter your age: ";
    std::cin >> age;
    std::cout << "You are " << age << " years old." << std::endl;

    return 0;
}

String Input¶

#include <iostream>
#include <string>

int main() {
    std::string name;

    std::cout << "Enter your name: ";
    std::cin >> name;  // Reads until whitespace

    std::cout << "Hello, " << name << "!" << std::endl;

    return 0;
}

Reading Entire Line¶

#include <iostream>
#include <string>

int main() {
    std::string fullName;

    std::cout << "Enter your name: ";
    std::getline(std::cin, fullName);  // Reads entire line

    std::cout << "Hello, " << fullName << "!" << std::endl;

    return 0;
}

5. using namespace std¶

To avoid typing std:: every time:

#include <iostream>
using namespace std;

int main() {
    cout << "Hello" << endl;  // std:: can be omitted
    return 0;
}

Considerations¶

Method	Advantages	Disadvantages
`std::cout`	Prevents name collisions	More typing
`using namespace std;`	Concise	Possible name collisions
`using std::cout;`	Compromise	Declare only what's needed

Recommendation: Use std:: explicitly in header files, and use using only in source files.

6. Comments¶

#include <iostream>

int main() {
    // Single-line comment

    /*
     * Multi-line comment
     * Also called block comment
     */

    std::cout << "Hello" << std::endl;  // Comment after code

    return 0;
}

7. IDE Setup¶

VS Code¶

Install C/C++ extension (Microsoft)
Install Code Runner extension (optional)
Configure tasks.json:

{
    "version": "2.0.0",
    "tasks": [{
        "label": "C++ Build",
        "type": "shell",
        "command": "g++",
        "args": [
            "-std=c++17",
            "-Wall",
            "-Wextra",
            "${file}",
            "-o",
            "${fileDirname}/${fileBasenameNoExtension}"
        ],
        "group": {
            "kind": "build",
            "isDefault": true
        }
    }]
}

Visual Studio¶

File → New Project → Console App
Automatically builds/runs

8. Differences Between C and C++¶

Header Files¶

// C style (usable but not recommended)
#include <stdio.h>
#include <stdlib.h>

// C++ style (recommended)
#include <cstdio>    // C++ version of C header
#include <cstdlib>
#include <iostream>  // C++ specific

I/O Comparison¶

// C style
#include <cstdio>

int main() {
    int num;
    printf("Number: ");
    scanf("%d", &num);
    printf("Input: %d\n", num);
    return 0;
}

// C++ style
#include <iostream>

int main() {
    int num;
    std::cout << "Number: ";
    std::cin >> num;
    std::cout << "Input: " << num << std::endl;
    return 0;
}

Key Differences¶

Item	C	C++
I/O	printf/scanf	cout/cin
Memory	malloc/free	new/delete
Strings	char[]	std::string
bool	None (use int)	bool type
Overloading	Not possible	Possible
Classes	Structs only	Class support

9. Practice Example¶

Simple Calculator¶

#include <iostream>

int main() {
    double num1, num2;
    char op;

    std::cout << "First number: ";
    std::cin >> num1;

    std::cout << "Operator (+, -, *, /): ";
    std::cin >> op;

    std::cout << "Second number: ";
    std::cin >> num2;

    double result;
    switch (op) {
        case '+': result = num1 + num2; break;
        case '-': result = num1 - num2; break;
        case '*': result = num1 * num2; break;
        case '/': result = num1 / num2; break;
        default:
            std::cout << "Invalid operator." << std::endl;
            return 1;
    }

    std::cout << num1 << " " << op << " " << num2
              << " = " << result << std::endl;

    return 0;
}

Execution:

First number: 10
Operator (+, -, *, /): +
Second number: 5
10 + 5 = 15

10. Summary¶

Concept	Description
`#include`	Include header file
`main()`	Program entry point
`std::cout`	Standard output
`std::cin`	Standard input
`std::endl`	Newline + buffer flush
`\n`	Newline character
`g++`	GNU C++ compiler

Next Steps¶

Let's learn about variables and types in 02_Variables_and_Types.md!