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Tricks of the Windows Gam…ming Gurus (2nd Edition)
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Disc2.iso
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vc98
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crt
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atox.c
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C/C++ Source or Header
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1998-06-17
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/***
*atox.c - atoi and atol conversion
*
* Copyright (c) 1989-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Converts a character string into an int or long.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdlib.h>
#include <ctype.h>
/***
*long atol(char *nptr) - Convert string to long
*
*Purpose:
* Converts ASCII string pointed to by nptr to binary.
* Overflow is not detected.
*
*Entry:
* nptr = ptr to string to convert
*
*Exit:
* return long int value of the string
*
*Exceptions:
* None - overflow is not detected.
*
*******************************************************************************/
long __cdecl atol(
const char *nptr
)
{
int c; /* current char */
long total; /* current total */
int sign; /* if '-', then negative, otherwise positive */
/* skip whitespace */
while ( isspace((int)(unsigned char)*nptr) )
++nptr;
c = (int)(unsigned char)*nptr++;
sign = c; /* save sign indication */
if (c == '-' || c == '+')
c = (int)(unsigned char)*nptr++; /* skip sign */
total = 0;
while (isdigit(c)) {
total = 10 * total + (c - '0'); /* accumulate digit */
c = (int)(unsigned char)*nptr++; /* get next char */
}
if (sign == '-')
return -total;
else
return total; /* return result, negated if necessary */
}
/***
*int atoi(char *nptr) - Convert string to long
*
*Purpose:
* Converts ASCII string pointed to by nptr to binary.
* Overflow is not detected. Because of this, we can just use
* atol().
*
*Entry:
* nptr = ptr to string to convert
*
*Exit:
* return int value of the string
*
*Exceptions:
* None - overflow is not detected.
*
*******************************************************************************/
int __cdecl atoi(
const char *nptr
)
{
return (int)atol(nptr);
}
#ifndef _NO_INT64
__int64 __cdecl _atoi64(
const char *nptr
)
{
int c; /* current char */
__int64 total; /* current total */
int sign; /* if '-', then negative, otherwise positive */
/* skip whitespace */
while ( isspace((int)(unsigned char)*nptr) )
++nptr;
c = (int)(unsigned char)*nptr++;
sign = c; /* save sign indication */
if (c == '-' || c == '+')
c = (int)(unsigned char)*nptr++; /* skip sign */
total = 0;
while (isdigit(c)) {
total = 10 * total + (c - '0'); /* accumulate digit */
c = (int)(unsigned char)*nptr++; /* get next char */
}
if (sign == '-')
return -total;
else
return total; /* return result, negated if necessary */
}
#endif /* _NO_INT64 */