java - 在字符串中打印整数时出错

Question

我是 Java 新手，正在阅读一本包含以下代码的书...

class Vehicle {
    int passengers;
    int fuelcap;
    int mpg;

    int range() {
        return mpg * fuelcap;
    }

    double fuelneeded(int miles) {
        return (double) miles / mpg;
    }
}

class TwoVehicles {
    public static void main(String args[]) {
        Vehicle minivan = new Vehicle();
        Vehicle sportscar = new Vehicle();
        double gallons;
        int dist = 252;

        minivan.passengers = 7;
        minivan.fuelcap = 16;
        minivan.mpg = 21;

        sportscar.passengers = 2;
        sportscar.fuelcap = 14;
        sportscar.mpg = 12;

        gallons = minivan.fuelneeded(dist);
        System.out.println("To go ", + dist + " miles minivan needs " + gallons + " gallons of fuel.");

        gallons = sportscar.fuelneeded(dist);
        System.out.println("To go ", + dist + " miles sportscar needs " + gallons + " gallons of fuel.");
    }
}

但是，在运行此代码时，我收到一条错误消息“错误:找不到 println(String,String) 的合适方法”。为什么会发生这种情况？

Answer 1

您不能将 System.out.println 与 2 参数一起使用，只能传递 1 字符串。

不在字符串内部的逗号(在字符串 "To go", 之后)，告诉编译器将字符串视为 2 个不同的参数。

更改此行:

System.out.println("To go ", + dist + " miles minivan needs " + gallons + " gallons of fuel.");

对此:

System.out.println("To go " + dist + " miles minivan needs " + gallons + " gallons of fuel.");