Write a program that prompts the user to enter the center and a point on the circle. the program should then output the circle’s radius, diameter, circumference, and area. your program must have at least the following functions: distance: this function takes as its parameters four numbers that represent two points in the plane and returns the distance between them.

Here is the code in C++.

#include <bits/stdc++.h>

using namespace std;

// function to calculate distance between two points

double distance(int a,int b,int c,int d )

{

 // return the distance between center and point

  return sqrt(pow(c - a, 2) +

               pow(d - b, 2) * 1.0);

}

// driver function

int main()

{

// variables to store coordinates

int x1,y1,x2,y2;

cout<<"Please Enter the center(x y) of the circle: ";

//reading center

cin>>x1>>y1;

cout<<"\nPlease Enter a point(x1 y1) on the circle:";

//reading point

cin>>x2>>y2;

// calling distance() function with 4 parameters

double rad=distance(x1,y1,x2,y2);

// calculating Radius and print

cout<<"Radius of circle is: "<<rad<<endl;

// calculating Diameter and print

cout<<"Diameter of circle is: "<<2*rad<<endl;

// calculating Circumference and print

cout<<"Circumference of circle is: "<<2*3.14*rad<<endl;

// calculating Area and print

cout<<"Area of circle is: "<<3.14*rad*rad<<endl;

return 0;

}

Explanation:

First it will read coordinates of center and point on the circle.The distancebetween center and point on circle is Radius. Call distance() function withfour parameters which are coordinates of center and point. This will return the value of Radius. Diameter is 2 times of Radius.Diameter of a circle is 2*3.14*Radius. and Area of the circle is calculate as 3.14*Radius*Radius. After finding these value print them.

Output:

Please Enter the center(x y) of the circle: 0 0

Please Enter a point(x1 y1) on the circle: 3 4

Radius of circle is: 5

Diameter of circle is: 10

Circumference of circle is: 31.4

Area of circle is: 78.5