Re: [Dev-C++] Char datatype

deeps6ix
 
         Well, even though other estimeed members have already answered this, let me explain why char is case-sensitive; I kinda get the feeling, by your question, you do not fully understand what a char is.         The datatype 'char' is a "virtual conception", in that a 'char' = 1 byte, and represents an entry of ASCII table.         The 'char' type does not exist in terms that it is really a integer. 
         Every entry of the ASCII table features a value and a charater. the first 31 entries consist of teletype control codes, like carriage return ( legacy typewriter thing, that you had to do when you wanted to change lines. )
         The following 96 entries features common letters, numbers and pontuaction stuff.
         This, obviously represents the first 127 entries, that are, also the maximum value a byte ( signed ) can achive...
         but looking into ASCII table reveals Value('M') = 77 and Value('m') = 109, therefore 'm' != 'M'         
Check out this code, execution gives more info :
<CODE LANG="C">         
#include <stdio.h>
int ReturnBytesInChar( unsigned char ch )    {    /* Right shhifts bits out, to AND with 0000 0001*/    int i;    for ( i=7*sizeof( char ) ; i >=0 ; i-- )      printf("%d", (ch >> i) & 1 );    }int ReturnBytesInInt( unsigned int ch )    {    int i;    for ( i=7*sizeof(int) ; i >=0 ; i-- )      printf("%d", ( ch >> i ) & 1);    }
int main ()       {      char a = 'a';   unsigned int  aIntegerValue = 97;   unsigned int Draw;   printf("Is a char = \'a\' equal a int = 97?\n\n");   if ( a == aIntegerValue )      printf("Wow, they do ? WTF!");   else       printf("Nah! this guys is full of bollogny"); // This will never happen!!! heheh humor, hehe   printf ("\n\nBut.. numbers of bytes allocatted for a char variable are %d and for a integer one %d\n...How can this be?", sizeof(char),sizeof(int));   printf("\n\nSimple dude :\n Check this table :\n");   for ( Draw^=Draw ; Draw != 9+sizeof(int)*7; Draw ++ ) putchar('-');   printf("\n\nChar bytes\t:\t%d\nVarDump:", sizeof( char ) );   ReturnBytesInChar( a );   printf("\n\nInt var bytes\t:\t%d\nVarDump:", sizeof( int ) );   ReturnBytesInInt( aIntegerValue );   putchar(10);   for ( Draw^=Draw ; Draw != 9+sizeof(int)*7; Draw ++ ) putchar('-');   printf("\nNotice the similarities ? from the %do byte to the %do of integer the value equals \rchar's %d byte%c\n", sizeof(unsigned int)-1, sizeof(unsigned int), sizeof(char), (sizeof(char)>1) ? 's':' ');      printf("What about diferent capitalizations? \'m\' and \'M\'?\nComputer see them as their values, and not letters...\n");   printf("See it as :\n\n\tAs value(\'m\') != value(\'M\') =>(implies)\n\t\t 'M' != 'm' \nAnd we can see it by the same functions above...");   printf("mess with them, and learn... and \rsee functions like fgetc() and try to understand why they are \'buggy\'");   scanf("%c",&a); }</CODE>
 


Date: Sat, 29 Mar 2008 11:20:28 +1200From: dee...@gm...: dev...@li...: [Dev-C++] Char datatypehello all,i would like to know if the CHAR datatype is case-sensitive??i.e. should i write code like this to recognise the character or note.g. char = category;if (category == 'M') or (category == 'm')cheers..-- ---Deepesh Kapadia--- 
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