Struct vs Class in C++

In C++, struct and class are nearly identical, with only one difference in their default access level.

Key Differences

Feature	Struct	Class
Default access modifier	public	private
Default inheritance	public	private
Intended use (convention)	Passive data structures	Objects with behavior

Example

struct Point {
    int x; // public by default
    int y; // public by default
};

class Circle {
private: // private by default, but explicitly shown for clarity
    Point center;
    double radius;
    
public:
    Circle(Point c, double r) : center(c), radius(r) {}
    double area() const { return 3.14159 * radius * radius; }
};

When to Use Each

• Use struct when you have a simple data structure with little or no behavior
• Use class when you have an object with both data and behavior that operates on that data
• Use struct when all members should be publicly accessible
• Use class when you need to enforce encapsulation by making some members private

The choice between struct and class is often a matter of convention and communicating intent to other programmers.