Unsuccessful Java Print Out of Red Black Binary Search Tree with Imports algs4.StdIn and util.Scanner in Visual Studio

Question

I'm trying to get printouts of the tree (i.e. st.keys()) in an old java program of a red black binary search tree using:

import java.util.Scanner;
AND

import edu.princeton.cs.algs4.StdIn;
import edu.princeton.cs.algs4.StdOut;

It doesn't seem to be working for reasons unknown to me. I tried debugging as a well. The program stops after the first for loop in both versions of main(). Any help in the right direction would be great.

Here are some images of the code with terminal output: alternative version of main() initial version of main()

Initial main() using import edu.princeton.cs.algs4.StdIn:

public static void main(String[] args) {
        RedBlackBST<String, Integer> st = new RedBlackBST<>();
        for (int i = 0; !StdIn.isEmpty(); i++) {
            String key = StdIn.readString();
            st.put(key, i);
        }
        StdOut.println();
        for (String s : st.keys())
            StdOut.println(s + " " + st.get(s));
        StdOut.println();
        //StdOut.println(st.check());
        st.delete("t");
        System.out.println(st.keys());
    }

Alternative main() using import java.util.Scanner:

public static void main(String[] args) {
        RedBlackBST<String, Integer> st = new RedBlackBST<>();
        
        Scanner input = new Scanner(System.in);

        for(int i=0; input.nextLine() != ""; i++){
            String key = input.nextLine(); // Use in.nextLine() for line-by-line reading
            
            st.put(key, i);

            System.out.println(input);
        }
        input.close();
        
        for (String s : st.keys()){
            System.out.println(s + " " + st.get(s));
        System.out.println();
        //StdOut.println(st.check());
        st.delete("t");
        System.out.println(st.keys());
        }
    }

Terminal Output (including user input):

  /usr/lib/jvm/java-11-openjdk-amd64/bin/java -Dfile.encoding=UTF-8 @/tmp/cp_do3cqf4bgpqm37l69q1dfdnql.argfile RedBlackBST 
t
a
l
l
t
r
e
e
s
^Z
[1]+  Stopped                 /usr/lib/jvm/java-11-openjdk-amd64/bin/java -Dfile.encoding=UTF-8 @/tmp/cp_do3cqf4bgpqm37l69q1dfdnql.argfile RedBlackBST

Answer 1

i get the proper output with ctrl+d, i was using ctrl+z to exit