istrint.cpp

来自「C标准库源代码」· C++ 代码 · 共 60 行

/***
* istrint.cpp - definitions for istream class operaotor>>(int) member functions
*
*       Copyright (c) 1991-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
*       Definitions of operator>>(int) member function(s) for istream class.
*       [AT&T C++]
*
*******************************************************************************/

#include <cruntime.h>
#include <internal.h>
#include <stdlib.h>
#include <limits.h>
#include <iostream.h>
#pragma hdrstop

/***
*istream& istream::operator>>(int& n) - extract int
*
*Purpose:
*       Extract int value from stream
*
*Entry:
*       n = value to update
*
*Exit:
*       n updated, or ios::failbit & n=INT_MAX/INT_MIN on overflow/underflow
*
*Exceptions:
*       Stream error on entry or value out of range
*
*******************************************************************************/
istream& istream::operator>>(int& n)
{
_WINSTATIC char ibuffer[MAXLONGSIZ];
    long value;
    char ** endptr = (char**)NULL;
    if (ipfx(0))
        {
        value = strtol(ibuffer, endptr, getint(ibuffer));
        if (value>INT_MAX)
            {
            n = INT_MAX;
            state |= ios::failbit;
            }
        else if (value<INT_MIN)
        {
            n = INT_MIN;
            state |= ios::failbit;
            }
        else
            n = (int) value;

        isfx();
        }
return *this;
}