java - 错误: '.class' expected amongst 7 other errors

Question

抱歉，我是一个 Java 编程初学者。有人能明白为什么我的程序给我这些错误消息吗？

错误消息如下:

MonthlyPhoneCostVer2.java:13: error: '.class' expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                           ^
MonthlyPhoneCostVer2.java:13: error: ';' expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                            ^
MonthlyPhoneCostVer2.java:13: error: <identifier> expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                       ^
MonthlyPhoneCostVer2.java:13: error: <identifier> expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                                 ^
MonthlyPhoneCostVer2.java:13: error: <identifier> expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                                           ^
MonthlyPhoneCostVer2.java:13: error: <identifier> expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                                                     ^
MonthlyPhoneCostVer2.java:13: error: <identifier> expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                                                               ^
MonthlyPhoneCostVer2.java:13: error: ';' expected
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
                                                                                        ^
8 errors

这是我的代码:

import javax.swing.*;
public class MonthlyPhoneCostVer2{
public static void main (String [] args){
double a = 2.50; // cost/min for day call
double b = 0.55; // cost/min for evening and weekend calls
double c = 50; // static monthly subscription cost
double d = 0.60; // cost for opening a phone call . cant have ',' in value
double x = Integer.parseInt(JOptionPane.showInputDialog(null, "Number of Phone Calls?"));
double y = Integer.parseInt(JOptionPane.showInputDialog(null, "Minutes of day calls"));
double z = Integer.parseInt(JOptionPane.showInputDialog(null, "Minutes of evening weekend calls"));
double res = isCost(double a, double b, double c, double d, double x, double y, double z);
JOptionPane.showMessageDialog(null, "Your Total Cost of Phone Fees is: " + res);
}
public static double isCost(double a, double b, double c, double d, double x, double y, double z){
return ((x*d) + (y*a) + (z*b) + c);
}
}

Answer 1

您对 isCost 的方法调用具有不正确语法。这个

double res = isCost(double a, double b, double c, double d, double x, double y, double z);

应该是

double res = isCost(a, b, c, d, x, y, z);

我不清楚为什么您觉得需要(再次)添加调用者的类型信息，但这根本不正确。