java处理命令行输入

Question

我试图实现一个 java 程序来处理来自命令行的用户输入。问题是在 Algorithms 一书中给出的(sedgewick )

1.1.21 Write a program that reads in lines from standard input with each line contain- ing a name and two integers and then uses printf() to print a table with a column of the names, the integers, and the result of dividing the first by the second, accurate to three decimal places. You could use a program like this to tabulate batting averages for baseball players or grades for students.

我尝试按如下方式实现这一点..但我坚持存储用户输入，以便可以使用 printf() 打印它..我认为 Scanner 适合获取用户输入..我似乎仍然无法存储输入以供以后使用。

Stack 类来自 sedgewick 的书。

知道如何解决这个问题吗？

 Scanner input = new Scanner(System.in);        
    Stack st = new Stack();
    while(input.hasNext()){
        String tkn =  input.next();
        st.push(tkn);           
        if (st.size()==3){
            int y = Integer.parseInt((String)st.pop());
            int x = Integer.parseInt((String)st.pop());
            String name = (String)st.pop();
            System.out.println("name="+name+",x="+x+",y="+y);

        }
    }

Answer 1

通过使用st.pop()它将删除并返回堆栈的最后一项。如果您不希望它被删除，您可以使用一个有序的Collection，例如 ArrayList并通过 list.get 访问该项目或使用Iterator .

另一个建议是创建一个对象来存储名称和 y、x 属性:

class MyObject {
    private String name;
    private int x;
    private int y;

   //... setter and getter methods for the properties
}

对代码的建议:它将输入推送到Stack中，然后弹出项目以创建MyObject并添加到列表 :

ArrayList listObjects = new ArrayList();
Scanner input = new Scanner(System.in);        
Stack st = new Stack();
while(input.hasNext()){
    String tkn =  input.next();
    st.push(tkn);           
    if (st.size()==3){
         int y = Integer.parseInt((String)st.pop());
         int x = Integer.parseInt((String)st.pop());
         String name = (String)st.pop();
         //create and add the object to the list for further use
         listObjects.add(new MyObject(name, x, y));
         System.out.println("name="+name+",x="+x+",y="+y);

     }
 }