C++ Program to Find Area of a Rectangle, Circle and Triangle with Class Diagram

This is a C++ program to find area of a rectangle, circle and triangle. Class diagram of program also given below.
Manually we can find the area of a rectangle by using equation:

Area = Breadth * Length.

Also we can find the area of a circle by using equation:

Area = 3.14 * (radius)²

Also we can find the area of a triangle by using equation:

a = length of first side
b = length of second side
c = length of third side
s = (a + b+ c)/2

Area = sqrt(s*(s-a)*(s-b)*(s-c))
-where sqrt stands for square root

Class Diagram

Class Name:areacalc

Data members:
arr[MAX]:int
count:int

Methods:
area(float)
area(int,int)
area(float,float,float)

Program Code

#include<math.h>
#include<iostream.h>
#include<conio.h>
class areacalc
{
private:
public:void area(float r);
void area(int a,int b);
void area(float a,float b,float d);
};
void areacalc::area(float r)
{ cout<<"Area of Circle="<<(3.14*r*r);
}
void areacalc::area(int a,int b)
{ cout<<"\n Area of Rectangle="<<(a*b);
}
void areacalc::area(float a,float b,float c)
{ float s,ar;
s=(a+b+c)/2;
ar= sqrt(s*(s-a)*(s-b)*(s-c));
cout<<"\nArea of Triangle="<<ar;
}

void main()
{ clrscr();
areacalc ac;
int r,a,b,c,d;
cout<<"\n Choose your option";
cout<<"\n...............................\n 1-rectangle\n 2-circle\n 3-triangle";
cout<<"\n Enter your choice :";
cin>>c;
switch(c)
{
case 1:cout<<"\n enter breadth and length:";
cin>>a>>b;
ac.area(a,b);
break;
case 2:cout<<"\n enter the radious of circle:";
cin>>r;
ac.area(r);
break;
case 3:cout<<"\n enter the three side of triangle:";
cin>>a>>b>>d;
ac.area(a,b,d);
break;
default:cout<<"invalid choice";
}
getch();
}

Sample Output

Choose your option
..............................

1-rectangle

2-circle

3-triangle

Enter your choice : 1

Enter Breadth and Length : 10

Area of rectangle = 200