what is the java syntax for saying
if x is not equal to a or b
I am trying to write an if else statement .. if a certain value is not equal to say 2 or 3 then do something else do something else :) thats confusing lol
7 Answers
Try this:
if (x != a && x != b) {
// Something (action x)
} else {
// Something else (action y)
}
Note that it's an "and" condition even though you're asking whether x is equal to a or b because each condition is negative. The other way you could represent this (if you find it more readable) is:
if (!(x == a || x == b)) {
// Something (action x)
} else {
// Something else (action y)
}
And at that point you may find it more readable still to get rid of the negation, but switch round what you do in the blocks:
if (x == a || x == b) {
// Action y
} else {
// Action x
}
These three blocks of code all do the same thing, but I think I'd find the bottom one the most readable as the condition is simple.
Comments
if ((x != a) && (x != b)) {
// do stuff
} else {
// do other stuff
}
Comments
if( x != a && x != b )
Notice it's an &&, not an ||
The condition ( x != 2 || x != 3 ) is always true: if x = 2, then x != 3 and the condition is true. if x = 1, then x != 2 and the condition is true.
What you're really saying is: if x is not one of 2 or 3, which is, x is not in the array [2,3], which is "x is not 2 neither 3", which is x != 2 and x != 3.
Comments
directly mimics the english sentence: if x is not equal to a or b
if (!(x == a || x == b))
{
doSomething();
}
else
{
somethingElse();
}
but if the extra not operator and parentheses hurts your eyes, use this(note the absence of the word Or in this condition, not anymore parallel with english sentence):
if (x != a && x != b)
{
doSomething();
}
else
{
somethingElse();
}
see my answer on programmer's ignorance pet peeve and Is it acceptable to only use the ‘else’ portion of an ‘if-else’ statement?, why i advocate constructing simple conditions(directly mimics english sentence, i.e. without sticky ANDs and too much NOTs)
1 Comment
Asaph
It's advisable to include the curly braces even though they are technically optional on one liners. Let's set a good example for the noobs.
if(x!=a && x!=b){
//do...
}
4 Comments
Asaph
Uppercase variable names is not recommended in Java.
hasen
@Asaph: as if that is the problem
Jon Skeet
@Asaph: They may be constants. More worrying is the fact that the condition is wrong... it should be an "and" rather than an "or".
Cesar
Thanks for pointing that out, corrected the answer. Think i need some sleep.
The code checks the value of x. If it’s not 2 and not 3, it prints the first message.
If x is 2 or 3, it prints the second message.
1 Comment
ahuemmer
Please take a look at How to answer and don't post code as pictures but copy & paste it using the formatting possibilities provided by StackOverflow.
in java if-else is a control statement which is used to test condition and transfer the control based on the evolution of condition.
if((x!='a')||(x!='b'))//if a,b is char use quotes else avoid
{
//if expression is true
}
else
{
//if expression is false
}
if you want that code should be executed when x=a and x=b both then use '&&' instead of '||'.
For more details:
2 Comments
Makoto
I'm not sure this adds anything to the existing answers.
Toby Speight
Not only that, but it's completely wrong - the expression is true whenever
x is not equal to both a and b. That's unlikely if a!=b.