atoi Post: 101539

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Top Forums Programming atoi Post 101539 by Rakesh Ranjan on Thursday 9th of March 2006 11:50:50 AM

03-09-2006

Registered User

bankpro, the function atoi just recognises
1) An optional string of tabs or spaces
2) An optional sign &
3) A string of digits

And upon recognising it converts it to int otherwise on failure it returns 0.
So if u try to convert a string like "name" u'll b getting 0 as it doesn't recognise it. If u try something like "22" or "-22" or even " -22" it would return int (here 22 or -22 as the case be).
I hope this clears ur doubt

Rakesh Ranjan

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atoi

ATOI(3) 						   BSD Library Functions Manual 						   ATOI(3)

NAME

     atoi, atoi_l -- convert ASCII string to integer

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <stdlib.h>

     int
     atoi(const char *str);

     #include <xlocale.h>

     int
     atoi_l(const char *str, locale_t loc);

DESCRIPTION

     The atoi() function converts the initial portion of the string pointed to by str to int representation.

     It is equivalent to:

	   (int)strtol(str, (char **)NULL, 10);

     While the atoi() function uses the current locale, the atoi_l() function may be passed a locale directly. See xlocale(3) for more informa-
     tion.

IMPLEMENTATION NOTES

     The atoi() and atoi_l() functions are thread-safe and async-cancel-safe.

     The atoi() and atoi_l() functions have been deprecated by strtol() and strtol_l() and should not be used in new code.

ERRORS

     The function atoi() need not affect the value of errno on an error.

SEE ALSO

     atof(3), atol(3), strtod(3), strtol(3), strtoul(3), xlocale(3)

STANDARDS

     The atoi() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1''), ISO/IEC 9899:1990 (``ISO C90''), and ISO/IEC 9899:1999 (``ISO C99'').

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								   June 4, 1993 							       BSD