好的。所以这里的情况。我的班级中有一个 calculateTax 方法，如下所示。
但我意识到我犯了一个很大的错误。“税”实际上是在课程开始时创建的一个字段。
private double tax;
这实际上应该是一个变量！
但是，当我在方法中将它创建为局部变量时，public double calculateTax(double tax)它可以工作，但是当我针对它运行测试时，它们会失败。我收到消息
The method calculateTax(double) in the type Salary is not applicable for the arguments ()
那么我哪里错了？
如何在不更改方法名称的情况下创建 tax 变量（仍然可以返回）？“calculateTax”方法需要保持不变。那么我在哪里以及如何创建“税”变量？提前致谢！
public double calculateTax() {
if (this.salary <= personalAllowance) { // If the salary is less
// £9440 (personal allowance) and below then no tax will be applied.
}
else if (this.salary <= taxThreshold) { // Else if the salary is less than or equal to the
// tax threshold then do the following:
double taxableSalary = this.salary - personalAllowance; // Salary take away the personal allowance
// equals the taxable salary.
this.tax = taxableSalary * 0.2; // The tax equal the taxable salary * 0.2 (20%)
}
else if (this.salary > 32010) {
double basicRate = taxThreshold * 0.2; // The basic rate tax is the tax threshold * 0.2
double difference = this.salary - taxThreshold; // The difference is the salary - the tax threshold
double highTax = difference - personalAllowance; // The high tax to be calculated is the difference
// take away personal allowance.
double highRate = highTax * 0.4; // The high rate tax is the high tax * the high tax value (40%)
this.tax = highRate + basicRate; // Total tax is the high rate tax (40%) + the basic rate tax (20%)
}
return tax;