c++中ifstream一次读取整个文件

c++中一次读取整个文件的内容的方法：

1. 读取至char*的情况

std::ifstream t; int length; t.open("file.txt"); // open input file t.seekg(0, std::ios::end); // go to the end length = t.tellg(); // report location (this is the length) t.seekg(0, std::ios::beg); // go back to the beginning buffer = new char[length]; // allocate memory for a buffer of appropriate dimension t.read(buffer, length); // read the whole file into the buffer t.close(); // close file handle // ... do stuff with buffer here ... 

1. 读取至std::string的情况：

第一种方法：

#include <string> #include <fstream> #include <streambuf> std::ifstream t("file.txt"); std::string str((std::istreambuf_iterator<char>(t)), std::istreambuf_iterator<char>()); 

第二种方法：

#include <string> #include <fstream> #include <sstream> std::ifstream t("file.txt"); std::stringstream buffer; buffer << t.rdbuf(); std::string contents(buffer.str()); 

reference

http://stackoverflow.com/questions/2602013/read-whole-ascii-file-into-c-stdstring

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