/* A sample program       file: 1ex1.cpp  ( or used as 1ex1.appended)

FALL 1998
___________________________________
Jacob Y. Kazakia   jyk0
July 14, 1998
Programming assignment 1 of week 1
Recitation Instructor: J.Y.Kazakia
Recitation Section  01
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Purpose: This program calculates the area of a sector of circle,
         given the radius of the circle in meters and the angle
         of the sector in degrees.
 
Algorithm: The area of the entire circle is given by the formula:
           Area = pi * radius * radius    ( here   pi = 3.1415927 )
		   
           If the sector angle is  theta degrees, then its area is:
           Sector_area = ( theta / 360 ) * pi * radius * radius
 
*/
 
include<iostream.h>         // header which contains the functions
                            // needed for input and output
 
const float PI = 3.1415927; // No one should be allowed to alter  
                            // this important constant
 
 
void main()
{

//  variables are typed and defined
 
 
float radius;   // the value of the radius of the circle (meters)
 
float theta;    // the angle of the sector (degrees)
 
float area;     // the area of the sector (square meters)


// prompt for and read the radius
 
cout<< endl<<"Enter the radius of the circle (in meters)  >>>";
 
cin>>radius;
 
// prompt for and read the sector angle
 
cout<< endl<<"Enter the angle of the sector (in degrees) >>>";
 
cin>>theta;

// Echo printing ( we must always double check ourselves and 
// others)
 
cout<<endl<<endl;
 
cout<<"We will now calculate the area of a sector of a circle"<<endl;
 
cout<<"The radius of the circle was given as :"<<radius ;
cout <<"meters"<<endl;
 
cout<<"The angle of the sector was given as: "<<theta ;
cout <<"degrees"<<endl;

// calculation ( do you really need a computer for this? )
 
area = (theta/360 )* PI * radius * radius;

cout<<endl<<"The area is calculated as : ";
cout <<area<< " square meters"<<endl;
cout<<endl<<endl;


cout<<" enter e (exit) to terminate the program";
char hold;
cin>>hold; }