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

FALL 1998
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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;
 
}