Studio: Area of a Circle
To get started, create a new console application in Visual Studio for the studio.
Calculate the Area of a Circle
Write a program that prompts the user for the radius of a circle. Calculate the area of the user’s circle and print the result.
Recall that the area of a circle is
A = pi * r * r where
r is the radius.
Here’s an example of how your program should work:
Enter a radius: 2.5 The area of a circle of radius 2.5 is: 19.625
Some questions to ask yourself:
- What data type should the radius be?
- What is the best way to get user input into a variable
radiusof that type?
System.Math class in C# to get the value of pi and square the radius.
documentation has guidance on how to use the
PI field and the
- Using the same radius, calculate the circumference (
2*pi*r) and diameter of the circle (
- Output the results.
- Ask the user for the miles per gallon of their car.
- If the radius that they entered is in miles, output how many gallons of gas they will use to go around this circle.
- Think about how we could make this program more modular by breaking out some of the code into a separate class. For example, we could pull out the circle information into a
Circleclass and leave the user questions and console messages in
Program. Take a look at the using statement for a refresher on how to reference another class file.
- Extend your program further by using a while or do-while loop , so that when the user enters a negative number they are re-prompted for a radius.
- Add additional validation to your program. If the user enters a non-numeric character or a empty string? Print an error message and quit. You’ll need to peek ahead to learn about conditional syntax in C# .