Function Overloading

Overloading

The overloading is a most important feature of object oriented programming. This feature enhances the capability of the method by allowing it to define it for different types of data.

Normally there are two types of overloading used in C++ ‒

1. Operator overloading

2. Function overloading

 

Function Overloading

The function overloading is a concept in which one can use many functions having the same function name but can pass different number of parameters or different types of parameters. For example, if there is a function sum which performs addition operation then one can use overloading functions like this ‒

int sum(int a,int b);

int sum(int a,int b,int c);

int sum(int a,int b,int c,int d);

Similarly the function overloading can be achieved like this ‒

int sum(int a,int b);

float sum(float a,float b);

double sum(double a,double b);

char sum(char a,char b);

That means we can handle different number of parameters or different types of parameters using the same function name.

Following program takes different number of parameters and performs the task of addition. Note that name of these functions is same and that is sum.

C++ Program

#include <iostream>

using namespace std;

class test {

private:

   int a,b,c,d;

public:

   int sum(int,int);

   int sum(int,int,int);

   int sum(int,int,int,int);

};

int test::sum(int a,int b)

{

   retum (a+b);

}

int test::sum(int a,int b,int c)

{

   return (a+b+c);

}

int test::sum(int a,int b,int c,int d)

{

   return (a+b+c+d);

}

void main()

{

   test obj;

   int a, b, c, d,choice;

   int result=0;

   cout<<"\n\t\t Main Menu":

   cout<"\n\t 1.Addition of two numbers";

   cout<"\n\t 2.Addition of three numbers":

   cout<<"\n\t 3.Addition of four numbers" <endl;

   cout<"\n Enter Your choice: ";

   cin choice;

   switch(choice)

   {

      case 1: cout<<"\nEnter 2 numbers: ";

         cin >> a >> b;

         result = obj.sum(a,b);

         break;

      case 2: cout<<"\nEnter 3 numbers: ";

         cin >> a >> b >> c;

         result = obj.sum(a,b,c);

         break;

      case 3: cout<<"\nEnter 4 numbers: ";

         cin >> a >> b >>c>> d;

         result = obj.sum(a,b,c,d);

         break;

      default: cout<<"\nWrong Choice";

         break;

}

cout<<"\n\nresult: " << result << endl;

getch();

}

Output

Main Menu

1.Addition of two numbers

2.Addition of three numbers

3.Addition of four numbers

Enter Your choice: 2

Enter 3 numbers: 10 20 30

result: 60

Now following program will take the parameters of different data types. This makes the function to overload.

C++ Program

#include<iostream>

using namespace std;

class test{

public:

   int sum(int,int);

   float sum(float,float);

   double sum(double,double);

};

int test::sum(int a,int b)

{

   return (a+b);

}

   float test::sum(float a,float b)

{

   return (a+b);

}

double test::sum(double a,double b)

{

   return (a+b);

}

void main()

{

   test obj;

   int choice;

   int a,b;

   float x,y;

   double m,n;

   double result=0;

   cout<<"\n\t\t Main Menu"

   cout<<"\n\t 1.Addition of two integer numbers";

   cout<<"\n\t 2.Addition of float numbers

   cout<<"\n\t 3.Addition of double numbers"<<endl;

   cout<<"\n Enter Your choice: ";

   cin >> choice;

   switch(choice)

   {

      case 1: cout <<"\nEnter 2 numbers:

         cin >> a >> b;

         result = obj.sum(a,b);

         break;

      case 2: cout<<"\nEnter 2 numbers: ";

         cin >> x >> y;

         result = obj.sum(x,y);

         break;

      case 3: cout <<"\nEnter 2 numbers: ";

         cin >> m >> n;

         result = obj.sum(m,n);

         break;

      default: cout<<"\nWrong Choice";

         break;

   }

   cout <<"\n\nresult: " << result << endl;

   getch();

}

Output

Main Menu

1.Addition of two integer numbers

2.Addition of float numbers

3.Addition of double numbers

Enter Your choice: 2

Enter 2 numbers: 1.13 5.6

result: 6.73

 

Example: 1

Write a program to find the area of a rectangle and triangle using function overloading

Solution :

#include <iostream>

using namespace std;

class Shape

{

public:

   int area(int length, int breadth);

   float area(float, int len, int br);

};

int Shape::area(int 1,int b)

{

   int result;

   result = 1*b;

   return result;

}

float Shape::area(float half,int 1,int b)

{

   float result;

   result = half*1*b;

   return result;

}

int main()

{

   Shape obj;

   cout<<"\n Area of Rectangle: " << obj.area(10, 20);

   cout<<"\n Area of Triangle: "<<obj.area(0.5, 10, 20);

   return 0;

}

Output

Area of Rectangle: 200

Area of Triangle: 100

 

Review Questions

1. Define function overloading with a simple example.

2. What do you mean by function overloading and exaplain it with an example ?

3. Discuss about function overloading with varying number of arguments and data types.