const class objects and functions

Author: anishsingh20

FunctionOverloading.cpp

@@ -28,8 +28,8 @@ int main () {
 	const Person p2; //used to access the const member function 
 
 	cout<<p2.x<<endl;
-	// p2.x=20; with a const object, its data members can never be changed till the lifetime of object.
-	
+	//p2.x=20; with a const object, its data members can never be changed till the lifetime of object.
+		
 
 
 	//1)  non-const object of class can be used to call and access the const members(variables and methods) of a class,but.

constClass.cpp

@@ -0,0 +1,58 @@
+#include<iostream>
+
+using namespace std;
+
+//const objects and const member functions
+
+class Person {
+	public:
+		//const class data member
+		int age;
+		string name;
+		//constructor
+		Person(int iage,string iname){
+			//age=iage; //initializing  const data age using constructor
+			age=iage;
+			name= iname;
+		}
+
+		void getage() const {
+			
+		cout<<"My age is-"<<age<<endl;
+		//age++; produces error as inside a const member function data members of class become const too and value cannot be changed once declared
+
+		}
+		
+		void getname() { //a non const function which cannot be called by a const object
+			
+			age++;
+			cout<<"My name is :"<<name<<endl;
+			
+		}
+};
+
+
+int main () {
+	
+	Person p(20,"anish");
+	Person const p1(30,"Mrinal"); // a const object and a data member cannot be changed using a const object throughtout its lifetime
+	
+	p.getage(); //const member function can be called using non-const object too.
+	p.getname();
+	p.age=25;
+	p.getage();//value of age is now 25
+
+	//using const object only for const member functions
+	p1.getage();
+	// p1.age=25; produces ERROR as when using a const member object,the class data members become constant too i.e read-only and cannot be changed once initialized
+	
+	//p1.getname(); ERROR as const object cannot call a non-const member function
+	
+	
+	
+
+	
+	
+	return 0;
+	
+}