std::basic_ios::operator!

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C++
 
输入/输出库
I / O操纵
C-风格的I / O
缓冲区
Original:
Buffers
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basic_streambuf
basic_filebuf
basic_stringbuf
strstreambuf（过时了）
流
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Streams
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抽象
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Abstractions
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ios_base
basic_ios
basic_istream
basic_ostream
basic_iostream
文件I / O
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File I/O
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basic_ifstream
basic_ofstream
basic_fstream
字符串I / O
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String I/O
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basic_istringstream
basic_ostringstream
basic_stringstream
阵列的I / O
Original:
Array I/O
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istrstream（过时了）
ostrstream（过时了）
strstream（过时了）
类型
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Types
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streamoff
streamsize
fpos
Error类的接口
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Error category interface
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iostream_category（C++11）
io_errc（C++11）
 
std::basic_ios
成员函数
Original:
Member functions
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basic_ios::basic_ios
basic_ios::~basic_ios
国家职能
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State functions
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basic_ios::good
basic_ios::eof
basic_ios::fail
basic_ios::bad
basic_ios::operator!
basic_ios::operator bool
basic_ios::rdstate
basic_ios::setstate
basic_ios::clear
格式化
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Formatting
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basic_ios::copyfmt
basic_ios::fill
杂项
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Miscellaneous
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basic_ios::exceptions
basic_ios::imbue
basic_ios::rdbuf
basic_ios::tie
basic_ios::narrow
basic_ios::widen
受保护的成员函数
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Protected member functions
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basic_ios::init
basic_ios::move
basic_ios::swap
basic_ios::set_rdbuf
 
bool operator!() const;
返回true如果发生了错误相关的流。具体而言，回报true如果badbit或failbit设置rdstate().
Original:
Returns true if an error has occurred on the associated stream. Specifically, returns true if badbit or failbit is set in rdstate().
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目录

[编辑] 参数

（无）
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(none)
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[编辑] 返回值

true如果已发生错误，false否则.
Original:
true if an error has occurred, false otherwise.
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[编辑] 为例

[edit]
#include <iostream>
#include <fstream>
#include <cstdlib>
int main()
{
    std::ifstream file("test.txt");
    if(!file)  // operator! is used here
    {  
        std::cout << "File opening failed\n";
        return EXIT_FAILURE;
    }
 
    // typical C++ I/O loop uses the return value of the I/O function
    // as the loop controlling condition, operator bool() is used here
    for(int n; file >> n; ) {
       std::cout << n << ' ';
    }
    std::cout << '\n';
 
    if (file.bad())
        std::cout << "I/O error while reading\n";
    else if (file.eof())
        std::cout << "End of file reached successfully\n";
    else if (file.fail())
        std::cout << "Non-integer data encountered\n";
}


[编辑] 另请参阅

ios_base::iostate flags basic_ios accessors
eofbit failbit badbit good() fail() bad() eof() operator bool() operator!()
false false false true false false false true false
false false true false true true false false true
false true false false true false false false true
false true true false true true false false true
true false false false false false true true false
true false true false true true true false true
true true false false true false true false true
true true true false true true true false true
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