reading a line from ifstream into a string variable

问题

In the following code :

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main() {
    string x = \"This is C++.\";
    ofstream of(\"d:/tester.txt\");
    of << x;
    of.close();


    ifstream read(\"d:/tester.txt\");
    read >> x;
    cout << x << endl ;
}

Output :

This

Since >> operator reads upto the first whitespace i get this output. How can i extract the line back into the string ?

I know this form of istream& getline (char* s, streamsize n ); but i want to store it in a string variable. How can i do this ?

回答1:

Use the std::getline() from <string>.

 istream & getline(istream & is,std::string& str)

So, for your case it would be:

std::getline(read,x);

来源：https://stackoverflow.com/questions/6663131/reading-a-line-from-ifstream-into-a-string-variable