Is there any limit on the number of conditions to be added in an if stmt

[Prashanth Kumar B R]

Hi,

I have situation in C++ where in I'll have to add around 20-25 conditions <compare a variable against a number> to an if statement.
Is there any limit on the number of expressions/conditions to be added to an if statement.

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++
sample code.
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++

x = 10;

if ( (x == 20) || (x == 22) || ) //I have around 20 comparisions here
{
//do something
}

if ( (x == 21) || (x == 22) )//I have around 20 comparisions here
{
//do something else
}
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++

Though the value of the 'x' is not any of the constants i am comparing with the stmts in all the if blocks are getting executed. i checked and re-checked the values to make sure that it is different but code isn't behaving as expected.

Can somebody help me.

Note that I can't use the switch the conditions as the constants in the if conditions are not mutually exclusive.

Thanks in advance
Prashanth

[JosAH]

@Prashanth Kumar B R
By definition they are mutually exclusive; have a look at Karnaugh maps; you can remodel your conditions such that you end up with a disjoint set of integer numbers that can be used in switch statements; but what I find more interesting: why are there so many conditions? Do you end up with less conditions if you consider the complement of the conditional expression?

kind regards,

Jos

[donbock]

@Prashanth Kumar B R
Your conditions are the logical-or of a bunch of subexpressions. The compiler will test each subexpression until it finds one that is true. It is normal for all subexpressions to be tested when they are all false.
(For the logical-and of a bunch of subexpressions, the compiler will test each subexpression until it finds one that is false.)

@JosAH
He has a sequence of if statements, not else if statements. Each value of x will execute a different combination of then-blocks.


Perhaps the code would be more concise if you moved each then-block into a separate subroutine and then used a switch statement. Each case would call one or more of those subroutines, corresponding to then-blocks you want activated for that value. This would make it easier to see at a glance what action is taken for each value of x.

[newb16]

@donbock
I understood it as his problem is that the body of 'if' is executed though condition seems to be false. ("Though the value of the 'x' is not any of the constants i am comparing with...")

[donbock]

@newb16
Then my guess is that somewhere among all those if statements he has one equals sign instead of two. Not only would that change the value of x, altering the path through subsequent if statements, but assignment to any nonzero value is considered true, causing execution of the then-block associated with that if.