Question

我一直在为一个我一直试图制作的简单计算器而经常出现这些错误信息：java：编译模块＆＃39;学习＆＃39;

时出错

Error:(24, 31) java: bad operand types for binary operator '*'
 first type:  java.util.Scanner
  second type: java.util.Scanner


Error:(27, 31) java: bad operand types for binary operator '/'
first type:  java.util.Scanner
second type: java.util.Scanner


 Error:(21, 31) java: bad operand types for binary operator '-'
 first type:  java.util.Scanner
 second type: java.util.Scanner


Error:(18, 31) java: bad operand types for binary operator '+'
 first type:  java.util.Scanner
  second type: java.util.Scanner


Error:(16, 16) java: incompatible types: java.util.Scanner cannot be converted to int

这是我的代码

import java.util.Scanner;

class Main {

public static void main(String[] args) {
    Scanner Operation = new Scanner(System.in);
    Scanner num1 = new Scanner(System.in);
    Scanner num2 = new Scanner(System.in);
    float result = 0;

    System.out.println("What is your first number?");
    int num1int = num1.nextInt();
    System.out.println("What is your second number?");
    int num2int = num2.nextInt();
    System.out.println("What operation would you like to perform?");
    switch (Operation) {
        case "addition":
            result = num1 + num2;
            break;
        case "subtraction":
            result = num1 - num2;
            break;
        case "multiplication":
            result = num1 * num2;
            break;
        case "division":
            result = num1 / num2;
            break;
    }

}

感谢您的帮助，对不起，如果我不应该发布这个，我是新的。

Answer 1

num1和num2不是数字，而是类型java.util.Scanner。

您可能会使用num1int和num2int，如下所示：

 switch (Operation) {
    case "addition":
        result = num1int + num2int;
        break;
    case "subtraction":
        result = num1int - num2int;
        break;
    case "multiplication":
        result = num1int * num2int;
        break;
    case "division":
        result = num1int / num2int;
        break;
}

我建议更改名称以反映真实类型，如下所示：

Scanner scannerNum1 = new Scanner(System.in);
Scanner scannerNum2 = new Scanner(System.in);
float result = 0;

System.out.println("What is your first number?");
int num1 = scannerNum1.nextInt();
System.out.println("What is your second number?");
int num2 = scannerNum2.nextInt();
switch (Operation) {
    case "addition":
        result = num1 + num2;
        break;
    case "subtraction":
        result = num1 - num2;
        break;
    case "multiplication":
        result = num1 * num2;
        break;
    case "division":
        result = num1 / num2;
        break;
}

注意：另外不需要定义两个扫描仪。一个就够了。

Answer 2

在您的代码中，您有

行

result = num1 + num2;

您尝试将num1和num2一起添加。鉴于变量名称，这似乎是合理的，但是当你考虑这些行时，它就变得荒谬了：

Scanner num1 = new Scanner(System.in);
Scanner num2 = new Scanner(System.in);

你不能添加两个扫描仪，这在理论上没有意义，而且在实践中它的含义更少。我假设你试图这样做：

result = num1int + num2int;

理论上这很好，但是当你尝试使用num1int = 3和num2int = 4进行此操作时，你得到的结果= 0而不是result = .75：

result = num1int / num2int;

这是因为整数除法总是向0舍入。将一个转换加倍以避免这种情况，如下所示：

result = ((double) num1int) / num2int;

我希望这有助于澄清您的问题。祝你好运！

使用简单的计算器遇到麻烦我一直试图制作

2 个答案: