Infolet

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:

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

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 #include #include 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="<>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

..............................
1-rectangle
2-circle
3-triangle