Can someone help me understand why I need an IF and WHILE for this answer?

Lucudzo :

Quick question- I have found the correct answer to this quiz question but I don't fully understand it.

here is the question-

Given a Scanner reference variable named input that has been associated with an input source consisting of a sequence of lines, write the code necessary to read in every line and print them all out on a single line, separated by a space.

here is the answer-

if(input.hasNext())
    System.out.print(input.nextLine());
    while (input.hasNext()){
        System.out.print(" " + input.nextLine());
    }
}

My question is, why does there need to be an if and while statement. I understand I need to first read in the line and then print it out. Why wouldn't it be sufficient to have just :

while(input.hasNext()){
    System.out.print(" " + input.nextLine());
}

Thank you

William A. :

The only noticeable difference is the fact that the correct answer doesn't produce an output starting with a space.

With this file:

foo
bar
baz

Your code will have this output (notice space in front of "foo"):

 foo bar baz

The answer's code will have this one (no space in front of "foo"):

foo bar baz