[英]Beginner Java: Variable Scope Issue
我正在练习我的 Java 书中的一些工作,但在获取使用变量进行计算的方法时遇到了问题。 请注意,这是一项正在进行的工作,我现在只是想让它使用 circleArea 方法来计算圆的面积。 这是必要的代码:
public class Geometry
{
public static void printMenu()
{
System.out.println("This is a geometry calculator\nChoose what you would like to calculate" + "\n1. Find the area of a circle\n2. Find the area of a rectangle\n3."
+ " Find the area of a triangle\n4. Find the circumference of a circle."
+ "\n5. Find the perimeter of a rectangle\n6. Find the perimeter of a triangle"
+ "\nEnter the number of your choice:");
}
public static void circleArea(double area)
{
System.out.println(Math.PI*Math.pow(radius, 2));
}
public static void main(String[] args)
{
int choice; //the user's choice
double value = 0; //the value returned from the method
char letter; //the Y or N from the user's decision to exit
double radius; //the radius of the circle
double length; //the length of the rectangle
double width; //the width of the rectangle
double height; //the height of the triangle
double base; //the base of the triangle
double side1; //the first side of the triangle
double side2; //the second side of the triangle
double side3; //the third side of the triangle
}
}
请声明一个类的变量并从中调用函数。
public class Geometry
{
int choice; //the user's choice
double value = 0; //the value returned from the method
char letter; //the Y or N from the user's decision to exit
double radius; //the radius of the circle
double length; //the length of the rectangle
double width; //the width of the rectangle
double height; //the height of the triangle
double base; //the base of the triangle
double side1; //the first side of the triangle
double side2; //the second side of the triangle
double side3; //the third side of the triangle
public static void printMenu()
{
System.out.println("This is a geometry calculator\nChoose what you would like to calculate"
+ "\n1. Find the area of a circle\n2. Find the area of a rectangle\n3."
+ " Find the area of a triangle\n4. Find the circumference of a circle."
+ "\n5. Find the perimeter of a rectangle\n6. Find the perimeter of a triangle"
+ "\nEnter the number of your choice:");
}
public static void circleArea(double area)
{
System.out.println(Math.PI*Math.pow(radius, 2));
}
public static void main(String[] args)
{
Geometry g = new Geometry();
g.printMenu();
}
}
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