CODEWITHSUNDEEP
javaloops
Tom
Tom

Reputation: 19

java input string and stop when 'stop' is entered

this is my code and I have a do-while loop which should carry on unless the string "text" entered is "stop". However when I compile the code it doesnt stop and stuck in an infinite loop. Pease help. Thanks.

import java.io.*;

public class input
{
    public static void main(String[] argv) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));  
        String text = "";  
        do
        {
            System.out.println("Please enter a string: ");
            text = br.readLine(); 
            System.out.println(text);
        }
        while (text != "stop");
    }
}

Upvotes: 0

Views: 16525

Answers (5)

PeterMmm
PeterMmm

Reputation: 24630

All posters are right: you should use String.equals().

Also you should complete understand String handling in Java. You will need it everywhere.

Even that String.equals should be used Java offers some "magic", that works even with your comparison. Keep learning !

public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String text = "";
        "stop".intern();
        do {
            System.out.println("Please enter a string: ");
            text = br.readLine().intern();
            System.out.println(text);
        } while (text != "stop");
    }

Upvotes: 0

khachik
khachik

Reputation: 28693

You cannot compare strings using ==. Use equals: while(!"stop".equals(text)).

Also since it comes from the user input, you might want to compare ignoring the case, you can use equalsIgnoreCase.

Upvotes: 0

Boris Pavlović
Boris Pavlović

Reputation: 64632

Replace

while (text != "stop")

with

while (!text.equals("stop"))

Upvotes: 0

Jesper
Jesper

Reputation: 206786

You are comparing strings with !=. That does not work in Java. You should use equals() to compare strings:

while (!text.equals("stop"));

Note that == and != on objects compare the references - i.e., if you use those operators on non-primitive variables, you are checking if the variables refer to the same object, and not if the content of those objects is the same.

Upvotes: 0

Nicolas Repiquet
Nicolas Repiquet

Reputation: 9255

Try replacing text != "stop" by !text.equals("stop")

!= is a reference equality test, .equals() is a logical equality test. Two strings can be different objects and still be logicaly equals (same content in this case).

Upvotes: 2

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