Problem with if statement - Char

**KardKaper** · 12-20-2009, 07:21 PM

Hey all.

I'm trying to write an IF statement that compares 3 characters: s, d and t with a user entered character.
Here's what i've got:

Java Code:

character = TextIO.getlnChar;

if(character != 's' && character != 'd' && character != 't'){

valid = false

}
else{

valid = true

}

What is wrong with this?

Thanks for the help.

Mike

**JosAH** · 12-20-2009, 07:29 PM

Originally Posted by KardKaper

Hey all.

I'm trying to write an IF statement that compares 3 characters: s, d and t with a user entered character.
Here's what i've got:

Java Code:

character = TextIO.getlnChar;

if(character != 's' && character != 'd' && character != 't'){

valid = false

}
else{

valid = true

}

What is wrong with this?

Thanks for the help.

Mike

Test your boolean expression by hand: suppose character == 'X'; it most certainly isn't an 's' or 'd' or 't' so your boolean expression is true. You didn't have this in mind but what did you have in mind?

kind regards,

Jos

**renamed** · 12-21-2009, 11:42 AM

Also remember that 's' != 'S'... it's case sensitive.

**helpisontheway** · 12-21-2009, 12:29 PM

not sure if this matters, but, you should prob use the || boolean or operator.... one constant cant equal three constants....

Java Code:

if(character != 's' || 'd' || 't')
{thing = true;}else{
thing = false}

i come from c++ origins... so that's how i would do it... i think the syntax would work in java... i don't see why it wouldn't

**renamed** · 12-21-2009, 12:45 PM

That doesn't work with Java!

**JosAH** · 12-21-2009, 01:10 PM

Originally Posted by renamed

That doesn't work with Java!

It doesn't work in C++ nor C either.

kind regards,

Jos

**renamed** · 12-21-2009, 01:21 PM

JosAH

I thought it didn't work with C++ but I tried it in Eclipse before posting and it worked.
I think it doesn't work with C.

**JosAH** · 12-21-2009, 01:43 PM

Originally Posted by renamed

JosAH

I thought it didn't work with C++ but I tried it in Eclipse before posting and it worked.
I think it doesn't work with C.

Well, in C or C++ it does something but likely not what the OP intended: the expression evaluates to (fully parenthesized)

((((character != 1) || 's') || 't') || 'd')

and just because all of 's' and 't' and 'd' evaluate to a non-zero value, the entire expression will be true; by sheer serendipity that is ;-)

kind regards,

Jos

**ProGenius** · 12-22-2009, 01:14 PM

Originally Posted by KardKaper

Hey all.

I'm trying to write an IF statement that compares 3 characters: s, d and t with a user entered character.
Here's what i've got:

Java Code:

character = TextIO.getlnChar;

if(character != 's' && character != 'd' && character != 't'){

valid = false

}
else{

valid = true

}

What is wrong with this?

Thanks for the help.

Mike

Try with a SWITCH statement. It may be a bit longer but at least you will be able to control what happenes with all of the alphabet letters. After you get itworking, try to change it to if else. That way you know what works and what doesnt. Thats
how I would do it