Category : OS/2 Files
Archive   : LJ2UP2.ZIP
Filename : STOI.C

/* STOI.C More powerful version of atoi.
*
* Copyright (C) 1985 by Allen Holub. All rights reserved.
* This program may be copied for personal, non-profit use only.
*/

/* Steve Coles - 7/1/88 Prototype added for MSC 5.1 */
int stoi(char * *instr);

#define islower(c) ( 'a' <= (c) && (c) <= 'z' )
#define toupper(c) ( islower(c) ? (c) - ('a' - 'A') : (c) )

int stoi(instr)
register char **instr;
{
/* Convert string to integer. If string starts with 0x it is
* interpreted as a hex number, else if it starts with a 0 it
* is octal, else it is decimal. Conversion stops on encountering
* the first character which is not a digit in the indicated
* radix. *instr is updated to point past the end of the number.
*/

register int num = 0 ;
register char *str ;
int sign = 1 ;

str = *instr;

while(*str == ' ' || *str == '\t' || *str == '\n' )
str++ ;

if( *str == '-' )
{
sign = -1 ;
str++;
}

if(*str == '0')
{
++str;
if (*str == 'x' || *str == 'X')
{
str++;
while( ('0'<= *str && *str <= '9') ||
('a'<= *str && *str <= 'f') ||
('A'<= *str && *str <= 'F') )
{
num *= 16;
num += ('0'<= *str && *str <= '9') ?
*str - '0' :
toupper(*str) - 'A' + 10 ;
str++;
}
}
else
{
while( '0' <= *str && *str <= '7' )
{
num *= 8;
num += *str++ - '0' ;
}
}
}
else
{
while( '0' <= *str && *str <= '9' )
{
num *= 10;
num += *str++ - '0' ;
}
}

*instr = str;
return( num * sign );
}

#ifdef TEST

main()
{
int num;
char numbuf[80], *p;

printf("Use ^C to exit\n");

while( 1 )
{
printf("string ( 0x.. 0.. ... ): ");
gets( p = numbuf );
num = stoi( &p ) ;
printf( "<%s> = %d = 0x%x = %o octal ", numbuf,num,num,num);
printf( "string tail = <%s>\n", p );
}
}

#endif