String Case

This is a discussion on String Case within the C++ Programming forums, part of the General Programming Boards category; What's the command for strings to ignore case? Is it strincmp? I want to compare user input to a coded ...

  1. #1
    For Narnia! Sentral's Avatar
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    String Case

    What's the command for strings to ignore case? Is it strincmp? I want to compare user input to a coded command such as, if you want to execute a command, type 'RUN', but say the user types 'run', I want the program to ignore the case, so it will recognize it. I think changing the user input to all CAPS or all lower letters would suffice, but I don't know the command. GRACIAS!

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    System Novice siavoshkc's Avatar
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    tolower()?
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    For Narnia! Sentral's Avatar
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    I thought this was for char only? Can this read in a lengthy string?

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    Case-insensitive C style string comparison is usually done with strcmpi or stricmp, but those are non-standard.

    You could change the string to all upper case using a single call to to the transform algorithm (and using toupper or tolower). Search for sample code since there is some small nuances due to the differences between std::toupper and ::toupper.

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    For Narnia! Sentral's Avatar
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    HMMMMMM......How about 'ToUpper()' instead of 'toupper' it seems like it is better for handling strings. Anyone think it's better?

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    Frequently Quite Prolix dwks's Avatar
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    I would use one of these:
    • strupper()
    • strtoupper()
    • toupperstr()

    Of course, I'm a C programmer.
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    >> How about 'ToUpper()' instead of 'toupper' it seems like it is better for handling strings.
    Never heard of it. If you're using .NET, then it might be better, but then why are you posting here?

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    >there is some small nuances due to the differences between std::toupper and ::toupper.
    That's interesting Daved. I tried transform using std::toupper, and got a compile error, and tried ::toupper and it compiled. Presumably std::toupper only saw the int version while ::toupper was able to locate the char version.

    I guess there's a difference between the location of std::toupper vs ::toupper.

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    For Narnia! Sentral's Avatar
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    Quote Originally Posted by Daved
    >> How about 'ToUpper()' instead of 'toupper' it seems like it is better for handling strings.
    Never heard of it. If you're using .NET, then it might be better, but then why are you posting here?
    I'm not using .NET, just trying to throw some ideas around.

    I also got a compiler error when using std::toupper(), I don't understand that 'int' conversion thingy. But the other one worked!

  10. #10
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    Well, toupper() is looking like a very odd function! What's the deal with this integer thing? Shouldn't the parameter accept the data type of 'string'? It can only convert one char, so how is an actual word changed to upper case with this function?

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    Umm...a loop?

    Here's a simple C program that makes use of toupper(), in case you don't understand:
    Code:
    #include <stdio.h>
    #include <ctype.h>
    
    int main(void)
    {
      char str[] = "OMG This iS sOmE SCRewy CRap";
      char *p;
    
      for(p = str;*p;p++)
        *p = toupper(*p);
    
      puts(str);
    
      return 0;
    }
    Code:
    itsme@itsme:~/C$ ./upperize
    OMG THIS IS SOME SCREWY CRAP
    itsme@itsme:~/C$
    Last edited by itsme86; 09-07-2006 at 05:27 PM.
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    For Narnia! Sentral's Avatar
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    O rly? I know that. But it's just inconvenient to have to create a loop and all that crap! Is it possible to create your own function similar to 'toupper' but with a string parameter? How can I look at the actual 'toupper' function code?

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    >> I'm not using .NET, just trying to throw some ideas around.
    If the ToUpper you were referring to is the .NET function, and you aren't using .NET, then I don't think it will work too well.

    >> how is an actual word changed to upper case with this function?
    It isn't. You change each character one at a time with either a loop or the transform algorithm I already mentioned. Using transform will allow you to do the whole string in a single line.

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    Is it possible to create your own function similar to 'toupper' but with a string parameter?
    Of course. And yes, it might contain a loop.
    How can I look at the actual 'toupper' function code?
    It's doubtful that you have the source for it on your computer. You could always try google of course to find some code that does it.
    If you understand what you're doing, you're not learning anything.

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    Ok, thanks! Me love you long time! Me give you EVERYTING LONG TIME!

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