C ++如何使用分隔符读取一行直到每行结束？
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C++ how to read a line with delimiter until the end of each line?
提问by weeo
Hi I need to read a file that looks like this...
嗨，我需要读取一个看起来像这样的文件...
1|Toy Story (1995)|Animation|Children's|Comedy
2|Jumanji (1995)|Adventure|Children's|Fantasy
3|Grumpier Old Men (1995)|Comedy|Romance
4|Waiting to Exhale (1995)|Comedy|Drama
5|Father of the Bride Part II (1995)|Comedy
6|Heat (1995)|Action|Crime|Thriller
7|Sabrina (1995)|Comedy|Romance
8|Tom and Huck (1995)|Adventure|Children's
9|Sudden Death (1995)|Action
As you can see the type of each movie can vary from 1 type to many...I wonder how could I read those until the end of each line?
正如你所看到的，每部电影的类型可以从一种类型到多种类型不等……我想知道我怎么能读到每一行的结尾？
I'm currently doing:
我目前正在做：
void readingenre(string filename,int **g)
{
ifstream myfile(filename);
cout << "reading file "+filename << endl;
if(myfile.is_open())
{
string item;
string name;
string type;
while(!myfile.eof())
{
getline(myfile,item,'|');
//cout <<item<< "\t";
getline(myfile,name,'|');
while(getline(myfile,type,'|'))
{
cout<<type<<endl;
}
getline(myfile,type,'\n');
}
myfile.close();
cout << "reading genre file finished" <<endl;
}
}
the result is not what I want...It looks like:
结果不是我想要的......看起来像：
Animation
Children's
Comedy
2
Jumanji (1995)
Adventure
Children's
Fantasy
3
Grumpier Old Men (1995)
Comedy
Romance
So it doesn't stop at the end of each line...How could I fix this?
所以它不会停在每一行的末尾......我怎么能解决这个问题？
回答by Sam Varshavchik
Attempting to parse this input file one field at a time is the wrong approach.
尝试一次解析这个输入文件一个字段是错误的方法。
This is a text file. A text file consists of lines terminated by newline characters. getline()by itself, is what you use to read a text file, with newline-terminated lines:
这是一个文本文件。文本文件由以换行符终止的行组成。getline()就其本身而言，它是您用来读取带有换行符终止行的文本文件的内容：
while (std::getline(myfile, line))
And not:
并不是：
while(!myfile.eof())
So now you have a loop that reads each line of text. A std::istringstreamcan be constructed inside the loop, containing the line just read:
所以现在你有一个循环来读取每一行文本。Astd::istringstream可以在循环内部构造，包含刚刚读取的行：
std::istringstream iline(line);
and then you can use std::getline(), with this std::istringstreamwith the optional delimiter character overriden to '|'to read each field in the line.
然后你可以使用std::getline(), 与std::istringstream可选的分隔符覆盖'|'来读取行中的每个字段。
