📜 Lecture 1: Programming Essentials in C++

This lecture introduces the C++ language, its setup, and the basic structure of a program.

Key Concepts

• What is C++?: It's a high-level, general-purpose programming language. It was developed as an enhancement of the C language to include Object-Oriented Programming (OOP).
• Why C++?: It's powerful, supports OOP, and allows for low-level memory access.
• Compilation: The process of converting Source Code (human-readable, e.g., main.cpp) into Machine Code (computer-readable, e.g., 1s and 0s) using a compiler.
• Basic Program Structure:
  • #include <iostream>: A preprocessor directive that includes the standard library for input/output operations (like cout).
  • using namespace std;: Tells the compiler to use the "standard" namespace, which avoids having to write std::cout.
  • int main(): The main function. Program execution always begins here.
  • cout << "Hello world!";: The standard output command. cout (see-out) prints the string to the console.
  • return 0;: Indicates that the program finished successfully.
  • ; (Semicolon): The statement terminator. It ends a command.
• Comments: Notes for humans, ignored by the compiler.
  • Single-line: // This is a comment.
  • Multi-line: /* This is a comment */.
• New Lines: To format output.
  • \n: The "newline" escape character, used inside a string.
  • endl: A command (end-line) used with cout.
• Variables & Data Types:
  • int: Integers (e.g., 15).
  • float / double: Fractional numbers (e.g., 2.3). double has more precision.
  • string: Text (e.g., "Mona").
  • char: A single character (e.g., 'A').
  • bool: true or false (outputs as 1 or 0).

#include <iostream> // Required for std::cout and std::endl
#include <string>   // Required for std::string

int main() {
    // Printing a simple string literal
    std::cout << "Hello, C++!" << std::endl;

    // Printing the value of an integer variable
    int age = 30;
    std::cout << "My age is: " << age << std::endl;

    // Printing the value of a string variable
    std::string name = "Alice";
    std::cout << "My name is: " << name << std::endl;

    // Chaining multiple outputs in a single statement
    double temperature = 25.5;
    std::cout << "Today's temperature is " << temperature << " degrees Celsius." << std::endl;

    return 0; // Indicates successful program execution
}