这个问题在这里已经有答案了：

整数除法：为什么1/3的结果==0(（16个答案）
24天前关门。
我的程序允许用户计算两个数字，然后根据用户输入的运算符执行简单的计算。所以我的源代码是：

System.out.print("Enter First Number: ");
    int num1 = scanNum.nextInt();

    System.out.print("Enter Second Number: ");
    int num2 = scanNum.nextInt();

    System.out.print("Enter Operator (+, -, * or /): ");
    char opt = scanOpt.next().charAt(0);

    scanNum.close();
    scanOpt.close();

    switch (opt)    
    {
        case '+':
            float result = num1 + num2;
            System.out.println(num1 + " " + opt + " " + num2 + " = " +result);
            break;

        case '-':
            result = num1 - num2;
            System.out.println(num1 + " " + opt + " " + num2 + " = " +result);
            break;

        case '*':
            result = num1 * num2;
            System.out.println(num1 + " " + opt + " " + num2 + " = " +result);
            break;

        case '/':
            result = num1 / num2;
            System.out.println(num1 + " " + opt + " " + num2 + " = " +result);
            break;

        default:
            System.out.println("Invalid Operator!");
            break;

它工作得很好，但是每当它将两个数字相除时，比如“6.0/4.0”，第十个小数点就不会出现。正确的输出应该是：

Enter First Number: 6
Enter Second Number: 4
Enter Operator (+, -, * or /): /
6 / 4 = 1.5

但使用我自己的源代码，结果是：

Enter First Number: 6
Enter Second Number: 4
Enter Operator (+, -, * or /): /
6 / 4 = 1.0