fstream中读取数据到map容器

从本地txt文件中读取不同类型数据到map中，怎么区分行尾标识符停止读取，转到下一行读取到map的key值里

std::basic_ios::eof< cpp‎ | io‎ | basic ios
bool eof() const;   
   

Returns true if the associated stream has reached end-of-file. Specifically, returns true if eofbit is set in rdstate().

See ios_base::iostate for the list of conditions that set eofbit.

Parameters(none)

Return valuetrue if an end-of-file has occurred, false otherwise.

NotesThis 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.

In typical usage, input stream processing stops on any error; eof() and fail() are then used to distinguish between different error conditions.

Example#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";
}



See alsoThe following table shows the value of basic_ios accessors (good(), fail(), etc.) for all possible combinations of ios_base::iostate flags:

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 
feof checks for the end-of-file
(function) 

ifstream ifs;
就是每次读取一行的
你试试
string line;
while(ifs>>line){
cout<<line<<endl;
}
这样就一行行打出来了