必需：Double，int Found：String，String

Question

这是我的代码： -

公共课程计划{

public static void main(String[] args) {
    if (args[0] == "interest"){
        public CompoundInerestCalculator(){
            CompoundInterestCalculator runCal = new CompoundInterestCalculator();
            if (args[1] == "annual"){
                runCal.compoundAnnually(args[2], args[3], args[4], args[5]);

            }

            else {
                args[1] = "continuous";
                runCal.continuousCompound(args[2], args[3], args[4]);
            }
        }   
    }

从中提取代码的下一个类：-

公共类CompoundInterestCalculator {

// Calculation for Annual Compound Interest
public BigDecimal compoundAnnually(double principal, double rate, int periods, int years) {
    double finalAmount = principal * Math.pow( 1 + ( rate / periods), years * periods);
    double compoundInterest = finalAmount - principal;
    BigDecimal finalInterest = new BigDecimal(compoundInterest);
    System.out.print(finalInterest);
        return finalInterest;
}

// Calculation for Continuous Compound Interest
public BigDecimal continuousCompound(double principal, double rate, int years) {
    double finalAmount = principal * Math.pow( Math.E, rate * years);
    double compoundInterest = finalAmount - principal;
    BigDecimal finalInterest = new BigDecimal(compoundInterest);
    System.out.print(finalInterest);
        return finalInterest;
}

}

这是我编译程序时的问题：

required：double，double，int，int

found：String，String，String，String

reason：实际参数String不能通过方法调用转换转换为double

Program.java:19：错误：类CompoundInterestCalculator中的方法ContinuousCompound无法应用于给定类型；

Answer 1

首先，将String与.equals not ==进行比较，因为在使用==比较对象时比较内存地址。

所以(args[0] == "interest")成为(args[0].equals("interest"))

其次，您将String s传递给声明为的方法

compoundAnnually(double principal, double rate, int periods, int years)

有了这个电话

runCal.compoundAnnually(args[2], args[3], args[4], args[5]);

您需要将它们解析为正确的类型...

runCal.compoundAnnually(Double.parseDouble(args[2]), Double.parseDouble(args[3]), Integer.parseInt(args[4]), Integer.parseInt(args[5]))

第三，将其应用于调用runCal.continuousCompound(args[2], args[3], args[4]);