I don't get why y = 100; is invalid, yet system.println("x is " + x); gives the output x is 40....

y = 100, is inside the main method... and so is x.... it seems a bit hypocritical that Y can't be used outside the if statement, yet X is used outside the if but holds the value of inside the if statement.... i really don't get how this works
Y inside if statement is declared, yet outside the if doesn't work..............BUT x is assigned value of 40 inside the if statement, yet still has the value of 40 outside it rather then 10 when it was originally initialized

when you see braces, you should think scope as a hierarchy. anything declared in an outer brace can be used inside (like x), whereas anything declared inside a brace (like y) cannot be used outside. didn't you take c#? it's the same way there.

exactly my point

x = y * 2; ------is used inside brace (if statement), yet it's still prints x = 40, instead of x = 10...... Just like Y = 20 in if statement, yet can't use outside, YET x still = 40.... they're declared in the same if statement yet 1 works outside it and the other doesn't

why would you expect x = 10? are you perhaps confusing the = operator? keep in mind = is the assignment operator, not an equation-equality statement like in math.

for example:
int firstNumber = 10; // firstNumber holds 10
int secondNumber = firstNumber + 1; // firstNumber holds 10, secondNumber holds 11
firstNumber = 50; // firstNumber holds 50, but secondNumber still holds 11, not 51

the equal sign = doesn't mean secondNumber will always contain a value 1 higher than firstNumber. the value firstNumber + 1 is computed at runtime and assigned to secondNumber. secondNumber will hold this value until you assign it a new one. exact same situation in your example, except the braces seem to be confusing you.

see how i specified the values in comments on a line-by-line basis? do that with your example to show me your reasoning.

This post was edited by carteblanche on Oct 17 2015 07:38am

It's the braces as you said.. I know how it'd act without them.... But ur not getting what i'm saying i don't think.....
(more specifically what's inside the IF statement), why is y = 100 excluded and not work when x = 40 does?

This post was edited by ferf on Oct 17 2015 08:32am

refer to my previous comment.



tell me, what is the scope of x and y? scope of x is the function, scope of y is the if block. you cannot use it out of scope.

if you're still confused, google for java variable scope.

This post was edited by carteblanche on Oct 17 2015 08:49am

Hmmm I think I understand it now, just seems weird logic to me....

perhaps you'll like javascript better?

http://jsfiddle.net/#&togetherjs=0FT8wnbVnP



// shows x=40, y=100

nah