Help with java, while loop

while (word != "dog") {
}

The compiler is looking for a variable named 'dog', instead of the string "dog".

 

Did you try the code:

Code:

while (word != "dog") {
}

 

I thought with strings you had to use the .equals method so:


while(!word.equals("dog")){

}

although, it has been awhile since I've worked with Java

 

Comparing pointers won't work. Use .equals.

-Lee

 

I'm sure that works in Java? At least it works in Python, which I've spent the last few months in...

 

It might work in Java if both strings have been interned (the static "dog" will have the variable might or might not). In general, unless you can be 100% sure, you should not compare two objects for content equality using pointer comparison.

 

That's close to a good solution, but would be better written as:

Code:

while(!"dog".equals(word))

This will not throw a NullPointerException, whereas the quoted solution would if word was null.

An even better (see: best) solution would be to use a utility function, found in something like the Apache Commons library:

Code:

while (!StringUtils.equals("dog", word))

 

This. I can't think of a reason to ever do (string1 == string2) even if they're both static. For clarity, always use the equals method.