if conditions

[Christoffer Blyerts]

Hi,

i get a bit confused sometimes of when a variable changes value or not in a if statement, for example:

int x=2;
if (x +2 > y) {}

x will be equal to 2 after this if statement.

if (x ++ > y)

In this case x will be equal to 3.


What are the rules for when the variable value gets changed or not within a if statement?


Thanks,

Christoffer

[Bear Bibeault]

This has nothing at all to do with if statements, but with the operators you are using. ++ modifies its operand, + does not.

[Guilherme Bazilio]

The ++ sign is an increment operator (assignment). Used to modify (increment in one) the variable.

x++;

This snippet willl only modify the value of x variable after it's current value has been used. So in that if statement it will be evaluated to 2.

++x;

On the other hand, this one will modify (increment) the x variable before using it. Then it comes to be 3 in the if statement.

++ modifies the variable!

The + sign is just an arithmetic operator used to sum values and return the result. So x + 2 will be returned to any variable that wants to receive it.

int y = 0;
int x = 2;

y = x + 2;

After that code, y will be 2. In the if statement, the result of the sum is not assigned to any variable. The variable x keeps its value since we are not assigning any value to it.