Question

尝试用Java编写一个简单的计算器，但是当我尝试编译它时，我一直遇到错误。不确定这是编码还是我在编译时所做的事情。任何帮助，将不胜感激！

import java.util.Scanner;

class simple calculator { // simple calculator
public static void main(String args[]){
   System.out.println("My simple calculator\n");
       Scanner bucky= new Scanner(System.in);
   double fnum,snum,ans;
   System.out.print("Enter the first and second " +
           "number : ");
   a=bucky.nextFloat(); //assign the numbers
   b=bucky.nextDouble(); // to respective variable
   System.out.println("What operation u want to " +
                                   "perform");
   String operation;
   operation=bucky.next();
   switch(operation) {
   case "+":
       ans=a + b;
   System.out.print("Sum of the two inputs = ");
           System.out.print(ans);
           break;
   case "-":
       ans=a - b;
    System.out.print("Subtraction of the two inputs = ");
            System.out.print(ans);
            break;
   case "*":
       ans=a * b;
    System.out.print("Multiplication of the two inputs = ");
            System.out.print(ans);
       break;
   case "/":
       ans=a / b;
    System.out.print("Division of the two inputs = ");
            System.out.print(ans);
            break;
default : System.out.println("Give a proper operation " +
                        "symbol ");

                break; // not required
   }

}
}

Answer 1

两个编译错误：

您的班级名称中有空格：class simple calculator不是有效的，因为＆＃34;计算器＆＃34;不是一个公认的令牌。尝试：class SimpleCalculator。同时将其公开并更改要匹配的文件的名称。（SimpleCalculator.java）。
您声明了变量a和b，但没有给出类型。使用float a = ...和double b = ...。那个是浮动而另一个是双重奇怪，但是按下......

需要注意的其他新问题：

您永远不会关闭扫描仪bucky。这是资源泄漏，在更大的应用程序中可能是一个主要的错误。在您阅读bucky.close()

operation = bucky.next()

名称bucky完全没有告诉我它是什么或它的用途。尝试使用描述性变量名称。（唯一的主要例外是循环索引的单字母名称等）。
fnum和snum是您声明但从不使用的局部变量。也许摆脱它们？

以下是您编辑的代码：

import java.util.Scanner;

public class SimpleCalculator { // simple calculator
    public static void main(String args[]){
        System.out.println("My simple calculator\n");
        Scanner bucky= new Scanner(System.in);
        double ans;
        System.out.print("Enter the first and second " +
                "number : ");
        float a=bucky.nextFloat(); //assign the numbers
        double b=bucky.nextDouble(); // to respective variable
        System.out.println("What operation u want to " +
                "perform");
        String operation;
        operation=bucky.next();
        bucky.close();
        switch(operation) {
        case "+":
            ans=a + b;
            System.out.print("Sum of the two inputs = ");
            System.out.print(ans);
            break;
        case "-":
            ans=a - b;
            System.out.print("Subtraction of the two inputs = ");
            System.out.print(ans);
            break;
        case "*":
            ans=a * b;
            System.out.print("Multiplication of the two inputs = ");
            System.out.print(ans);
            break;
        case "/":
            ans=a / b;
            System.out.print("Division of the two inputs = ");
            System.out.print(ans);
            break;
        default : System.out.println("Give a proper operation " +
                "symbol ");

        break; // not required
        }
    }
}

我能够毫无困难地在终端编译它。

简单计算器Java编码错误

1 个答案: