java - 初学者循环 GUI

Question

我必须制作一个 CD 计算器的 GUI。

I put in the Initial investment ($): e.g. 2000
the Annual interest rate (%): e.g. (8%)
Ending value ($): e.g. 5000

程序然后在 jLabel 上输出:所需的年数为“12”(例如)

我需要制作一个 do while 循环和一个计数器。

我从 3 个文本字段中获取文本，然后添加带有年利率 % 的初始投资，但循环和计数器遇到问题？

int initialInvestment, endValue, cdvalue;
double cdValue, annualDecimalConvert, annualRate;

initialInvestment = Integer.parseInt(initialInvestmentInput.getText());
annualRate = Double.parseDouble(interestRateInput.getText())/100;
endValue = Integer.parseInt(endingValueInput.getText());

cdValue = initialInvestment + (initialInvestment * annualRate);

double a = cdValue;
while (a <= endValue){
    a = a++;
    yearsOutput.setText("The required year needed is: " + a);
}

Answer 1

您只需在循环的每次迭代中将 1 添加到 a 即可。因此，需要几千次迭代才能满足循环要求。

您要做的就是每年不断增加利息，同时计算年份，并且仅在循环完成后更新输出。

int initialInvestment, endValue;
double cdValue, annualDecimalConvert, annualRate;

initialInvestment = Integer.parseInt(initialInvestmentInput.getText());
annualRate = Double.parseDouble(interestRateInput.getText())/100;
endValue = Integer.parseInt(endingValueInput.getText());

// First year interest is counted here.
cdValue = initialInvestment + (initialInvestment * annualRate);
int years = 1;

while (cdValue < endValue){
  cdValue = cdValue + (cdValue * annualRate);
  years++;
}

yearsOutput.setText("The required year needed is: " + years);