控制台应用程序显示的圆半径答案不正确

Question

只是制作一个简单的控制台应用程序，向用户显示圆的面积。使用我当前的代码，收到的结果是 "The area of the circle is: geometry" 而不是数值。我整天都在努力，却一无所获......我确定我在做一些非常愚蠢的事情，所以任何指导都将不胜感激。

public static void circle() {
    int radius;
    geometry circleArea = new geometry();

    Console.Write("\nEnter The Radius Of Your Circle:  ");
    radius = Convert.ToInt32(Console.ReadLine());

    Console.Write("\nThe area of the circle is: {0:f3}", circleArea);
    // wait
    Console.ReadLine();
}

// calculate the area of a circle
public double squareSum(int radius) {
    return (Math.PI * (radius * radius));
}

Answer 1

Console.Write("\nThe area of the circle is: {0:f3}", squareSum(radius));

控制台应用程序显示的圆半径答案不正确

Console application is displaying incorrect answer for radius of a circle

c#

console-application