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error C2143: syntax error : missing ')' before 'constant

Answer 1

+6 A:

How many open parentheses do you have?

How many closed parentheses do you have?

Are these the same number? If not, where is one missing?

Also, the syntax a == (b,c,d) is not shorthand for a == b || a == c || a == d like you seem to think. It's actually equivalent to a == d due to the way the comma operator works.

To be completely explicit, what you actually want is this:

while (selection == 'a' || selection == 'b' ||
       selection == 'c' || selection == 'd' ||
       selection == 'e' || selection == 'f' ||
       selection == 'g' || selection == 'h' ||
       selection == 'i' || selection == 'A' ||
       selection == 'B' || selection == 'C' ||
       selection == 'D' || selection == 'E' ||
       selection == 'F' || selection == 'G' ||
       selection == 'H' || selection == 'I')
{
   /* Do stuff */
}

Or, to be a lot more consice about it, you can take advantage of the fact that the letters are arranged alphabetically in the ASCII table, and write

while (tolower(selection) >= 'a' && tolower(selection) <= 'i')
{
   /* Do stuff */
}

This requires inclusion of <ctype.h> for the tolower function.

Tyler McHenry 2010-05-25 18:49:18

In addition to that, the OP really don't want to compare 'selection' to the result of the comma operator.

nos 2010-05-25 18:51:30

well when i add a closed parentheses it gives me this along with the the original error:\error C2059: syntax error : ')'this is what the line looks like when i add the closed parentheses: while (selection == ('a','b','c', 'd', 'e', 'f', 'g', 'h', 'i','A','B' 'C', 'D', 'E', 'F', 'G', 'H', 'I'));

2010-05-25 18:51:45

further hint - while loop definition doesn't normally end with a ; unless you don't want it to do anything

Greg Domjan 2010-05-25 18:52:50

so how should i write the line out without having to use all the commas. i need to include the letter A through I (lowercase and uppercase)

2010-05-25 18:53:27

when i take ; out it says that im missing the semicolon. now im confused.

2010-05-25 18:55:37

I suggest you find a good introductory book on C. You seem to be confused about the basic syntax of a `while` loop, which is somewhat below the level at which you can get useful help from the Internet.

Tyler McHenry 2010-05-25 18:59:02

there is a missing , between 'B' and 'C' thus breaking the CSV list and causing the expectation of a ) before the 'C' - that would fix the syntax but not resolve process issue you have

Greg Domjan 2010-05-25 18:59:29

Answer 2

+1 A:

Given your comments on Tyler's post, it seems like what you really want is:

while ((selection >= 'a' && selection <= 'i') || (selection >= 'A' && selection <= 'I'))
{
    // loop
}

Characters can be compared as if they were numbers (because they are numbers in the CPU), which means that you can check for a range of characters using the < > <= >= operators.

JSBangs 2010-05-25 18:56:27

YES!! thank you, thank you, thank you!!!

2010-05-25 18:59:20

Just note that while this works on PCs, it can break on (for example) IBM mainframes. They use EBCDIC instead of ASCII, and EBCDIC has some non-alphabetic characters between some of the letters -- something like half a doze between 'i' and 'j', and the same number between 'r' and 's'. Likewise with the upper-case letters. [Warning: my memory of the exact letters could be a bit off].

Jerry Coffin 2010-05-25 19:14:47

or make it e.g. : `while(strchr("abcdefghiABCDEFGHI",selection) != NULL) { ... } `

nos 2010-05-26 09:26:01

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