C++ Classes and Objects

Overview

Classes and objects are core concepts of object-oriented programming. A class is a blueprint or template for objects, defining the properties (data members) and behaviors (member functions) of objects. An object is an instance of a class, a concrete entity. As an object-oriented programming language, C++ provides powerful class mechanisms to organize and manage code.

🏗️ Basic Concepts of Classes

Class Definition and Declaration

#include <iostream>
#include <string>

// Basic class definition
class Student {
private:
    std::string name_;
    int age_;
    double gpa_;
    
public:
    // Constructor
    Student(const std::string& name, int age, double gpa) 
        : name_(name), age_(age), gpa_(gpa) {}
    
    // Member functions
    void displayInfo() const {
        std::cout << "Name: " << name_ << ", Age: " << age_ 
                  << ", GPA: " << gpa_ << std::endl;
    }
    
    // Accessors (getters)
    std::string getName() const { return name_; }
    int getAge() const { return age_; }
    double getGPA() const { return gpa_; }
    
    // Mutators (setters)
    void setAge(int age) { 
        if (age > 0) age_ = age; 
    }
    
    void setGPA(double gpa) { 
        if (gpa >= 0.0 && gpa <= 4.0) gpa_ = gpa; 
    }
};

int main() {
    std::cout << "=== Classes and Objects Basics ===" << std::endl;
    
    // Create objects