Question

我有一个班级项目，我的老师要我使用double类型作为我的号码，但是当roudning达到最接近的美元时，我需要使用和特殊功能或格式化。

这是我到目前为止所拥有的：

//Variable Declarations
    String name;
    int hoursWorked;
    double hourlyPayRate;
    double federalTaxRate;
    double stateTaxRate;
    double grossPay;
    double netPay;
    double totalDeduction;

    //Getting user inputs
    Scanner input = new Scanner(System.in);
    System.out.print("Enter employee's name: ");
    name = input.next();
    System.out.print("Enter number of hours worked in a week: ");
    hoursWorked = input.nextInt();
    System.out.print("Enter hourly pay rate: ");
    hourlyPayRate = input.nextDouble();
    System.out.print("Enter federal tax withholding rate: ");
    federalTaxRate = input.nextDouble();
    System.out.print("Enter state tax withholding rate: ");
    stateTaxRate = input.nextDouble();
    System.out.println();

    //Amount Calculations
    grossPay = hoursWorked * hourlyPayRate;
    totalDeduction = (grossPay * federalTaxRate) + 
            (grossPay * stateTaxRate);

    //Printing Payroll Statement
    System.out.println("Employee Name: " + name);
    System.out.println("Hours Worked: " + hoursWorked);
    System.out.println("Pay Rate: $" + hourlyPayRate);
    System.out.println("Gross Pay: $" + grossPay);
    System.out.println("Deductions: ");
    System.out.println("\tFederal Withholding (" + (federalTaxRate * 100) +
            "%): $" + (grossPay * federalTaxRate));
    System.out.println("\tState Withholding (" + (stateTaxRate * 100) +
            "%): $" + (grossPay * stateTaxRate));
    System.out.println("\tTotal Deduction: $" + totalDeduction);
    System.out.println("Net pay: $" + (grossPay - totalDeduction));

我的输出与此类似：

Enter employee's name: Bob
Enter number of hours worked in a week: 25
Enter hourly pay rate: 10.30
Enter federal tax withholding rate: .2
Enter state tax withholding rate: .09

Employee Name: Bob
Hours Worked: 25
Pay Rate: $10.3
Gross Pay: $257.5
Deductions: 
    Federal Withholding (20.0%): $51.5
    State Withholding (9.0%): $23.175
    Total Deduction: $74.675
Net pay: $182.825

我需要联邦托管，国家托管，总扣除和净工资等产出四舍五入到最近的便士，因为这些都是美元金额。

Answer 1

在不使用库函数的情况下将正double舍入到最近的int的最简单方法是：

static int round(double d) {
    return (int)(d + .5);
}

这是有效的，因为将一个浮点数转换为int 会截断数字的非整数部分。

Answer 2

您需要知道的是小数位数千分之一的数字。我得到的方法是先将小数点移动到你想要舍入的位置。（shift = netPay * 100）

接下来你需要摆脱小数点左边的一切。我会利用类型铸造。（千分之一=移位 - （整数）移位）

然后你有一个简单的if语句来知道是向上舍入还是向下舍入。四舍五入（netPay = netPay - （千分之一/ 100））

对它进行整理（netPay = netPay +（（千分之一）/ 100）

我希望这会有所帮助。

在java中舍入而不使用任何特殊函数或格式

2 个答案: