读一个std :: ifstream到一个向量的行 [英] Reading an std::ifstream to a vector of lines

问题描述

我如何在一个文件中读取每行是一个数字，然后将该数字输出到一个向量行？

例如：file.txt包含：

  314 
 159 
 265 
 123 
 456 $ b b 
 
 
 
我尝试过这个实现：
  vector< int> ifstream_lines（ifstream& fs）{
 vector< int>出口; 
 int temp; 
 getline（fs，temp）; 
 while（！fs.eof（））{
 out.push_back（temp）; 
 getline（fs，temp）; 
} 
 fs.seekg（0，ios :: beg）; 
 fs.clear（）; 
 return out; 
} 
  
但是当我尝试编译时，我会得到如下错误：
 错误C2784：'std :: basic_istream< _Elem，_Traits> & std :: getline 
（std :: basic_istream< _Elem，_Traits>&，std :: basic_string< _Elem，_Traits，_Alloc>&）'：
无法推导' std :: basic_istream< _Elem，_Traits> &'from'std :: ifstream'
  
因此，显然有些错误。有比我所想的更优雅的解决方案吗？ （假设第三方库不支持Boost）
 
 
 
谢谢！
解决方案
 p>我怀疑你想要这样的东西：
  #include< vector& 
 #include< fstream> 
 #include  
 std :: vector< int>出口; 
 
 std :: ifstream fs（file.txt）; 
 
 std :: copy（
 std :: istream_iterator< int>（fs），
 std :: istream_iterator< int>（），
 std :: back_inserter （out））; 
  
 
How would I go about reading in a file where each line is a single number, then outputing that number into a vector of lines?

eg: file.txt contains:
314
159
265
123
456
I have tried this implementation:
vector<int> ifstream_lines(ifstream& fs) {
    vector<int> out;
    int temp;
    getline(fs,temp);
    while (!fs.eof()) {
        out.push_back(temp);
        getline(fs,temp);
    }
    fs.seekg(0,ios::beg);
    fs.clear();
    return out;
}
but when I attempt to compile, I get errors such as:
error C2784: 'std::basic_istream<_Elem,_Traits> &std::getline
(std::basic_istream<_Elem,_Traits> &,std::basic_string<_Elem,_Traits,_Alloc> &)' : 
could not deduce template argument for 'std::basic_istream<_Elem,_Traits> &' from 'std::ifstream'
so, obviously, something is wrong. Is there a more elegant solution than what I am trying? (Assuming 3rd party libraries like Boost are unavailable)

Thanks!
解决方案
I suspect you want something like this:
#include <vector>
#include <fstream>
#include <iterator>

std::vector<int> out;

std::ifstream fs("file.txt");

std::copy(
    std::istream_iterator<int>(fs), 
    std::istream_iterator<int>(), 
    std::back_inserter(out));


                        
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