Java重载方法

Question

我试图使用一个文件在命令窗口中创建一个菜单.用户从这些菜单选项中进行选择.系统会提示他们输入一个数字.该数字传递给两个重载方法,这些方法确定数字是整数还是浮点数.计算完成后,结果将打印到屏幕上,菜单重新出现.这是我的两个文件中的代码.

MyMathOpsTest类:

import java.util.Scanner; // import Scanner class
public class MyMathOpsTest
{
   //method to pause until a key is pressed
   public static void pause() 
   { 
       try 
   { 
       System.out.print("Press <Enter> to continue..."); 
       System.in.read(); 
   } 
       catch (Exception e)
       {
           System.err.printf("Error %s%c\n",e.getMessage(),7);
       }
}//end pause

public static void main( String args[] )
{
    //variables to capture keyboard input
    Scanner keyBd = new Scanner( System.in );
    char selection;
    //int selection;

    do{//display menu
        System.out.println( "1. Square a Number");
        System.out.println( "2. Cube a Number");
        System.out.println( "3. Raise a Number to a Power");
        System.out.println( "4. Maximum of Three Numbers");
        System.out.println( "5. Minimum of Three Numbers");
        System.out.println( "6. Exit");
        System.out.print( "Selection[1-6]: " );

        //get menu selection
        selection = keyBd.next().charAt(0);
        //selection = keyBd.nextInt();

        //process menu selection
        switch (selection){
            case '1':
                MyMathOpsTest.squareTheNumber();
                pause();
                break;
            case '2':
                MyMathOpsTest.cubeTheNumber();
                pause();
                break;
            case '3':                
                MyMathOpsTest.raiseTheNumber();
                pause();
                break;
            case '4':                
                MyMathOpsTest.maximumNumber();
                pause();
                break;
            case '5':                
                MyMathOpsTest.minimumNumber();
                pause();
                break;
                case '6':
                //recognize as valid selection but do nothing
                break;
            default :
                System.out.printf("%c\n",7);
                System.out.println("Invalid Selection");
        }//end switch

    }while( selection != '6');
} // end method main

public static void squareTheNumber()
{

}

public static void cubeTheNumber()
{
}

public static void raiseTheNumber()
{
}

public static void maximumNumber()
{
MyMathOps.maximum();
}

public static void minimumNumber()
{
}

} // end class MyMathOpsTest

MyMathOps类:

import java.util.Scanner;

public class MyMathOps
{
public static int square(x:Integer):Integer
{
}

public static double square(x:Double):Double
{
}

public static int cube(x:Integer):Integer
{
}

public static double cube(x:Double):Double
{
}

public static int maximum(x:Integer, y:Integer, z:Integer):Integer
{
    // create Scanner for input from command window
    Scanner input = new Scanner( System.in );
    // obtain user input
    System.out.print( "Enter three integer values separated by spaces: ");
    int numberl = input.nextInt();
    // read first integer
    int number2 = input.nextInt();
    // read second double
    int number3 = input.nextInt();
    // read third double
    // determine the maximum value
    int result = maximum( numberl, number2, number3 );
    // display maximum value
    System.out.println( "Maximum is: " + result );
} // end method maximum

public static double maximum(x:Double, y:Double, z:Double):Double
{
    // create Scanner for input from command window
    Scanner input = new Scanner( System.in );
    // obtain user input
    System.out.print( "Enter three floating-point values separated by spaces: ");
    number1 = input.nextDouble();
    // read first double double
    number2 = input.nextDouble();
    // read second double
    double number3 = input.nextDouble();
    // read third double
    // determine the maximum value
    double result = maximum( numberl, number2, number3 );
    // display maximum value
    System.out.println( "Maximum is: " + result );
} // end method maximum

public static int minimum(x:Integer, y:Integer, z:Integer):Integer
{
    // create Scanner for input from command window
    Scanner input = new Scanner( System.in );
    // obtain user input
    System.out.print( "Enter three integer values separated by spaces: ");
    int numberl = input.nextInt();
    // read first integer
    int number2 = input.nextInt();
    // read second double
    int number3 = input.nextInt();
    // read third double
    // determine the minimum value
    int result = minimum( numberl, number2, number3 );
    // display minimum value
    System.out.println( "Minimum is: " + result );
} // end method minimum

public static double minimum(x:Double, y:Double, z:Double):Double
{
    // create Scanner for input from command window
    Scanner input = new Scanner( System.in );
    // obtain user input
    System.out.print( "Enter three floating-point values separated by spaces: ");
    number1 = input.nextDouble();
    // read first double double
    number2 = input.nextDouble();
    // read second double
    double number3 = input.nextDouble();
    // read third double
    // determine the minimum value
    double result = minimum( numberl, number2, number3 );
    // display minimum value
    System.out.println( "Minimum is: " + result );
} // end method minimum

} // end class MyMathOps

这段代码是我自己键入的代码和我的教科书中的示例代码的组合.这不会在jGRASP中为我编译.我收到这些错误.

MyMathOps.java:10: <identifier> expected
   public static int square(x:Integer):Integer
                              ^
MyMathOps.java:96: ')' expected
    } // end method minimum
     ^
2 errors

----jGRASP wedge: exit code for process is 1.
----jGRASP: operation complete.

我在这做错了什么？我花了几个小时研究这个并阅读我的教科书.如果我没有做到这一点.我的成绩会很差.我需要在这堂课上取得好成绩才能进入顶尖的计算机科学大学.谢谢你的帮助.

在极少数情况下,我的导师或盐湖社区学院的任何管理员都遇到过这个问题,让我明确表达我的意图.这个问题是以最大的学术诚信精神张贴的.我要求这个问题寻求一般性的建议,并帮助理解使用Java编程语言的正确方法.我绝不会使用他人的作品,而是把它当作我自己的作品.我使用这里提供的答案作为我理解的一般帮助.我做自己的所有工作,不复制回答我的问题的人提供的工作.

Answer 1

像这样的行不是有效的Java语法:

public static int square(x:Integer):Integer
public static int maximum(x:Integer, y:Integer, z:Integer):Integer
...

这看起来像UML或伪代码语法."x:Integer"是"语言无关"符号,表示x是Integer类型(映射到Java中的int或Integer对象).最后的":Integer"表示该方法返回一个Integer类型,您已经正确执行了该类型.

尝试将所有方法声明更改为如下所示:

public static int square(int x) // Or "Integer x" if you want to use the Integer class, rather than the primitive int
public static int maximum(int x, int y, int z)
....