Question

I want to write a C++ program to read the diameter of a circle. The program should find and display the area and circumference of the circle. Define a constant of type double PI = 3.14159

I need code for this program

Answer 1

#include <iostream>

const double PI = 3.14159;

int main() {

double diameter;

std::cout << "Please enter the diameter of the circle:" << std::endl;

std::cin >> diameter;

double radius = diameter / 2;

double area = radius * radius * PI;

double circumference = 2 * radius * PI; // or diameter * PI;

std::cout << "Area: " << area << std::endl;

std::cout << "Circumference: " << circumference << std::endl;

}

Step-by-step explanation:

The first line imports the read/write library. The rest should be self-explanatory.

std::cin is the input stream - we use it to get the diameter

std::cout is the output stream - we write the answers (and commentary) there.

std::endl is the special "character" informing the output stream that we want it to put a newline character (and actually print to the output - it might have been holding off on it).

the // in the circumference computation signifies a comment - the program simply ignores this. I've added it to tell the reader that the circumference could have been computed using the diameter,