Lecture 34 - Display Area Of Circle

To display the area of a circle, you can write a C++ program that takes the radius as input from the user and calculates and displays the area of the circle. The formula to calculate the area of a circle is:

Area = π * radius * radius

Where π (pi) is approximately 3.14159.

Here's a C++ program to display the area of a circle:

cppCopy code

#include <iostream> #include <cmath> // Include the cmath library for the value of pi int main() {    const double pi = 3.14159;    double radius, area;    std::cout << "Enter the radius of the circle: ";    std::cin >> radius;    // Calculate the area of the circle    area = pi * pow(radius, 2);    std::cout << "The area of the circle with radius " << radius << " is: " << area << std::endl;    return 0; }

In this program, we first define the value of π (pi) as a constant. Then, we declare variables radius and area to store the user input and the calculated area, respectively. The user is prompted to enter the radius, and then the area is calculated using the formula and displayed on the console.

Note that we use the pow function from the cmath library to calculate the square of the radius.

Feel free to run this program with different values of the radius to see the corresponding areas of the circles.