java processing input from command line

Question

I was trying to implement a java program to process user input from command line.The problem was one given in Algorithms book (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.

I tried to implement this as follows..but I am stuck in storing the user input sothat it can be printed using printf() ..I thought Scanner would be appropriate for getting the user input..Still I can't seem to get the input stored for later use.

The class Stack is from sedgewick's book.

Any idea how to get this right?

 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);

        }
    }

damon 1 2\n jon 2 3\n jim5 6\n and Ctrl-D to terminate input — damon
– damon, Commented Jun 11, 2013 at 4:08

fmodos · Accepted Answer · 2013-06-11 04:21:19Z

By using the st.pop() it will remove and return the last item of the stack. If you dont want it to get removed you can use one ordered Collection like ArrayList and access the item by list.get or using an Iterator.

Another suggestion is to create one object to store the name and the y, x properties:

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

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

Suggestion for your code: it pushes the input in the Stack, then pop the items to create the MyObject and add to the list:

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);

     }
 }

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