实例化对象编译错误

Question

我一直在研究Java程序，学习如何使用和创建构造函数。由于某种原因，我不断收到错误，通知我在实例化对象时我的程序找不到符号。

下面是资源类：

public class Pizza
{
   private int size;
   private String topping;
   private double cost;

   public Pizza()
   {
      size = 10;
      topping = "cheese";
      cost = 9.00;
   }
   public Pizza(int s, String t, double c)
   {
      s = size;
      t = topping;
      c = cost;
   }
   public int getSize() {
      return size;
   }
   public void setSize(int s) {
      s = size;
   }
   public String getTopping(){
      return topping;
   }
   public void setTopping(String t){
      topping = t;
   }
   public void setCost(double c) {
      cost = c;
   }   
   public double getCost(double c){
      return cost;
   }

   public String toString()
   {
      return String.format("%d inch %s pizza will cost $%,.2fn", size, topping, cost);
   }
}

下面是驱动程序类：

public class PizzaTest
{
   public static void main(String[] args)
   {
      Pizza orderTwo = new Pizza();
      System.out.printf("%-25s %s", "Pizza #1", orderTwo);
   }
}

我一直在仔细检查代码，但我似乎找不到任何语法错误。任何建议不胜感激。 编译器错误：

PizzaTest.java:6: error: cannot find symbol Pizza orderTwo = new Pizza();
^ symbol: class Pizza location: class PizzaTest
PizzaTest.java:6: error: cannot find symbol Pizza orderTwo = new Pizza();
^ symbol: class Pizza location: class PizzaTest
2 errors

Answer 1

您很可能需要从 PizzaTest 类导入对 Pizza 类的引用。

import <packagename>.Pizza;

Answer 2

显然Pizza与PizzaTest位于不同的包中，并且您尚未将适用的import语句添加到PizzaTest中。

Answer 3

这是错误所在

   public Pizza(int s, String t, double c)
   {
      s = size;
      t = topping;
      c = cost;
   }

它应该是相反的方式

   public Pizza(int s, String t, double c)
   {
      sise = s;
      topping = t;
      cost = c;
   }

同样在 setSize（） 函数中，您也可以以相反的方式使用它

Answer 4

此方法中不应存在参数，请删除double c

public double getCost(double c){
  return cost;
}