Using strings inside of "if" statements

[SubMatrix]

I am trying to use an if statement to compare strings and it doesn't appear to be working. The format I am using is:

if (stringname = "value")
do this;

However this doesn't seem to work, unless I'm missing something it it looks like it pretty much ignores the if statement altogether despite ways I change it around. Any help would be appreciated.

[reinkesm]

Two things. First, what you should use for checking String equality is:

if (stringname.equals("value")) {
 // stuff!
}

If you use the == operator, it actually compares the address of the String objects which isn't what you want.

Second, using a single = means assignment. So in your original if statement, it sets the variable stringname's value to "value", and the if statement evaluates to true because it was successful. A little wierd I know.

When doing a compare, use two ==. Here is how an if comparing two ints would look:

int a = 0;
int b = 1;
if (a == b) {
 // more stuffs!
}

[SubMatrix]

Thanks, it works now. I meant to put the "==" in the example as it was what I was using I just keep forgetting little stuff like that without the compiler to scream at me .

[cjard]

just remember:

primitives start with a lowercase letter:

int boolean byte short float double long char

and you compare those with ==

if( myInt == 1)


--------------------------------------

Objects start with an Uppercase Letter:

String s = "hello";
File f;
System.out.println //System is an object
Character c;
Integer i; //the primitives all have Object equivalents, for special uses.

you compare the CONTENT of 2 objects with .equals():
object1.equals(object2)


you compare MEMORY ADDRESSES of 2 objects, with ==
this is used occasionally, say for if a button handler is handling 10 buttons, and it is told which button generated the event :

if buttonThatGeneratedTheEvent == saveButton{
save()
}
else if buttonThatGeneratedTheEvent == quitButton{
quit()
}


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simple rule is: use == for primitives and .equals for objects