read

read_file.c++

std::ifstream in("some.file"); 
std::istreambuf_iterator<char> beg(in), end; 
std::string str(beg, end);

// or

std::ifstream in("some.file"); 
std::ostringstream tmp; 
tmp << in.rdbuf(); 
std::string str = tmp.str();

// 读取文件并按行遍历
std::ifstream in("some.file");
std::string line;
while(std::getline(in,line))
{
}