PrintStream类型中的方法println(double)不适用于参数(String,double)

Question

这是代码:

import java.util.Scanner;

public class MoviePrices {
    public static void main(String[] args) {
        Scanner user = new Scanner(System.in);
        double adult = 10.50;
        double child = 7.50;
        System.out.println("How many adult tickets?");
        int fnum = user.nextInt();

        double aprice = fnum * adult;
        System.out.println("The cost of your movie tickets before is ", aprice);

    }
}

我对编码很新,这是我的学校项目.我试图在该字符串中打印变量aprice但我收到标题中的错误.

Answer 1

而不是这个:

System.out.println("The cost of your movie tickets before is ", aprice);

做这个:

System.out.println("The cost of your movie tickets before is " + aprice);

这称为"连接".阅读此Java跟踪以获取更多信息.

编辑:你也可以使用格式PrintStream.printf.例如:

double aprice = 4.0 / 3.0;
System.out.printf("The cost of your movie tickets before is %f\n", aprice);

打印:

以前的电影票价为1.333333

你甚至可以这样做:

double aprice = 4.0 / 3.0;
System.out.printf("The cost of your movie tickets before is $%.2f\n", aprice);

这将打印:

以前的电影票价是1.33美元

的%.2f可以读作"格式(的%),其为数字(f)用2位小数(的.2)".在$前面的在%是作秀,顺便说一句,这不是比说:"把这里$"等格式字符串的一部分.您可以在Formatterjavadocs中找到格式规范.