Question about BufferedReader

[Shen Lin]

The task is typing in some people's names and the output should be random pairs of these people. e.g.
[awana]abc: java Pairs
james
alex
jane
james and jane
alex
My program is shown below:

 
import java.io.*;
import java.util.*;
public class Pairs{
    
    public static void randomPairs(Set names){
String[] theArray = new String[names.size()];
int index = 0;
Iterator i = names.iterator();
while(i.hasNext()){
    theArray[index++] = (String)i.next();
}
for(int j = 0; j < names.size() / 2; j++){
    int pos = j * 2;
    System.out.println(theArray[pos] + "and" + theArray[pos + 1]);
}
System.out.println(theArray[names.size() - 1]);

    }
    
    public static void main(String[] args) throws java.io.IOException{
Set nameSet = new TreeSet();
BufferedReader br = 
    new BufferedReader(new InputStreamReader(System.in));
String line = br.readLine();
while(line != null){
    nameSet.add(line);
    line = br.readLine();
}

randomPairs(nameSet);

    }
}
 

When running this program, the method randomPairs(nameSet) cannot be reached since the program cannot break out from the while-loop. I wonder how the method randomPairs(nameSet) can be executed after the while-loop.
Thanks,
Shen

[Richard Jensen]

Originally posted by Shen Lin:
When running this program, the method randomPairs(nameSet) cannot be reached since the program cannot break out from the while-loop. I wonder how the method randomPairs(nameSet) can be executed after the while-loop.
Thanks,
Shen

When the input stream closes then the buffered reader will return null for the readLine.
So, if you run from the command line you need to enter your names (one per line) and then enter the appropriate end of stream character for your OS (on Windows it is Ctrl-Z).
It would also work by redirecting the contents of a file containing one name per line.

java Pairs < names.txt