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javabufferedreaderinputstreamreader

What does this condition do (BufferredReader and InputStreamReader)?

I'm currently reading a code and i found a method starting like this :

BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));  

String userInput;

while ((userInput = stdIn.readLine()) != null) {

  }

Can someone explain me the condition while ? That a = b != c seems weird to me.

Solution

  • Seems like your eyes are glancing over a pair of parentheses:

    while ( (userInput = stdIn.readLine() ) != null) {

}

    I've attempted to make it more clear above.

    The variable userInput is being assigned stdIn.readLine(). And while userInput isn't null following that assignment, the loop continues.

    It's just a one-liner for handling the userInput update, as well as checking for null