Index
In C++, both struct and class are used to define custom data types. However, they have some key differences in terms of access control. Let’s explore the differences between struct and class with examples.
Key Differences between struct and class
- Data Members :
struct: Members of astructarepublicby default.class: Members of aclassareprivateby default.
- Usage:
struct: Typically used for simple data structures without complex functionality.class: Typically used for objects with both data and behavior (methods).
Example: Struct vs Class
Let’s consider an example where we define a struct and a class with the same members.
Code for struct:
#include <iostream>
using namespace std;
struct Rectangle {
int length; // Public by default
int breadth; // Public by default
int area() {
return length * breadth;
}
};
int main() {
Rectangle rect;
rect.length = 10;
rect.breadth = 5;
cout << "Area (using struct): " << rect.area() << endl;
return 0;
}
Output:
Area (using struct): 50
Code for class:
#include <iostream>
using namespace std;
class Rectangle {
int length; // Private by default
int breadth; // Private by default
int area() {
return length * breadth;
}
};
int main() {
Rectangle rect;
cout << "Area (using class): " << rect.area() << endl;
return 0;
}
Output:
ERROR!
/tmp/1ZiwDa1cAK.cpp: In function 'int main()':
/tmp/1ZiwDa1cAK.cpp:17:48: error: 'int Rectangle::area()' is private within this context
17 | cout << "Area (using class): " << rect.area() << endl;
| ~~~~~~~~~^~
/tmp/1ZiwDa1cAK.cpp:9:9: note: declared private here
9 | int area() {
| ^~~~
Correct Code for class:
#include <iostream>
using namespace std;
class Rectangle {
int length; // Private by default
int breadth; // Private by default
public:
void setDimensions(int l, int b) {
length = l;
breadth = b;
}
int area() {
return length * breadth;
}
};
int main() {
Rectangle rect;
rect.setDimensions(10, 5); // Use a public method to set dimensions
cout << "Area (using class): " << rect.area() << endl;
return 0;
}
Output:
Area (using class): 50