[c++][语言语法]stringstream iostream ifstream

时间:2023-12-29 10:53:50

c++中ifstream一次读取整个文件

读取至char*的情况

  1. 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

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());