std::basic_ios::eof
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bool eof() const; |
||
返回true相关联的数据流,如果已达到文件结束。具体而言,回报true如果
eofbit
在rdstate().原文:
Returns true if the associated stream has reached end-of-file. Specifically, returns true if
eofbit
is set in rdstate().目录 |
[编辑] 参数
(无)
[编辑] 返回值
true的端部的文件,如果已经发生,false否则.
原文:
true if an end-of-file has occurred, false otherwise.
[编辑] 注释
此功能仅报告最近的I / O操作流的状态,不检查相关的数据源。例如,如果最近的I / O是一个
get()
,它返回一个文件的最后一个字节,eof()
回报false。接下来的get()
无法读取任何东西,设置eofbit
。只有这样,eof()
回报true.原文:
This function only reports the stream state as set by the most recent I/O operation, it does not examine the associated data source. For example, if the most recent I/O was a
get()
, which returned the last byte of a file, eof()
returns false. The next get()
fails to read anything and sets the eofbit
. Only then eof()
returns true.在典型的使用中,输入流处理停止的任何错误;
eof()
和fail()然后用于区分不同的错误条件.原文:
In typical usage, input stream processing stops on any error;
eof()
and fail() are then used to distinguish between different error conditions.[编辑] 示例
#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 |
检查文件结束 (函数) |