MealDataTotal.java:25:错误:类MealData中的构造函数MealData无法应用于给定类型;新的MealData(“ Burger”,5.99,650.0),^必需:无参数找到:字符串,双,双原因:实际参数和正式参数列表的长度不同
class MealData
{
public String name;
public double price;
public double calories;
String MealData (String n,double p,double c)
{
name = n;
price = p;
calories = c;
String summaryString;
summaryString = name + ", $" + Double.toString(price) + ", " + Double.toString(calories) + " calories";
return summaryString;
}
}
public class MealDataTotal extends MealData
{
MealData[] MainCourses = new MealData[]
{
new MealData("Burger", 5.99, 650.0),
new MealData("Sandwich", 3.99, 450.0f),
new MealData("Mac 'n Cheese", 4.99, 500.0)
};
public static void main(String []args)
{
System.out.println("Hello World");
}
}
一个结构确实有一个返回值,它返回该类的实例,这就是为什么您不应该声明返回类型的原因。
如果要以自定义方式将实例转换为字符串,请覆盖toString
方法。