C++ Basics and Syntax

C++ was created by Bjarne Stroustrup in 1979 as an extension to the C language. It adds object-oriented features while maintaining the speed and low-level memory control of C.

1. Anatomy of a C++ Program

Let's look at the classic "Hello, World!" program in C++ to understand its basic structure.

cpp

#include <iostream>
 
using namespace std;
 
int main() {
    cout << "Hello, World!" << endl;
    return 0;
}

Breakdown of the code:

#include <iostream>: This is a preprocessor directive. It tells the compiler to include the standard input/output stream library, which allows us to print to the screen.
using namespace std;: This tells the compiler to use the standard (std) namespace. Without this, we would have to write std::cout and std::endl.
int main(): This is the main function where the execution of the program begins. It returns an integer (int).
cout << "Hello, World!" << endl;: cout (character output) is used to print text. << is the insertion operator. endl inserts a newline character and flushes the output stream.
return 0;: This terminates the main() function and returns the value 0 to the operating system, signaling that the program executed successfully.

2. Variables and Data Types

C++ is a strongly typed language, meaning every variable must be declared with a specific data type before it can be used.

cpp

int age = 20;           // Integer (whole number)
float pi = 3.14f;       // Floating point number (decimals)
double precisePi = 3.14159265; // Double precision floating point
char letter = 'A';      // Single character
bool isPassed = true;   // Boolean (true or false)

3. Input and Output

C++ uses streams for input and output operations.

cout (Console Output): Used to print data.
cin (Console Input): Used to read data from the keyboard.

cpp

#include <iostream>
using namespace std;
 
int main() {
    int age;
    cout << "Enter your age: ";
    cin >> age; // Reads an integer from the user
    cout << "You are " << age << " years old." << endl;
    return 0;
}

Summary

C++ programs begin execution in the main() function.
The <iostream> library is required for standard console input (cin) and output (cout).
Variables must be explicitly typed (e.g., int, float, char).
The std namespace contains all the standard C++ library components.

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C++ Basics and Syntax

C++ Basics and Syntax

1. Anatomy of a C++ Program

Breakdown of the code:

2. Variables and Data Types

3. Input and Output

Summary

Key Concepts

The main() Function

Standard Library (iostream)

Namespaces

Quick Check

Object Oriented Programming

Object Oriented Programming