读取文件内容并保存到string中

(最近在调整生物钟，晚上9点半前睡觉，早晨很早就醒了，利用早晨充足的时间可以读英语和写代码，感觉很好。) 不知道你是否考虑过这个问题：std::string究竟可以存储多大的字符串呢？理论上std::string可以存储 std::string::max_size大小的内容。
我在Visual studio 2008上运行的结果是：max_size:4294967294

#include <iostream> // std::cout#include <fstream> // std::ifstream#include <string>
using namespace std;
bool readFileToString(string file_name, string& fileData){ bool ret = false; ifstream file(file_name.c_str(), std::ifstream::binary);     if(file) { // Calculate the file's size, and allocate a buffer of that size. file.seekg(0, file.end); const int file_size = file.tellg(); char* file_buf = new char [file_size+1];      //make sure the end tag '\0' of string.
        memset(file_buf, 0, file_size+1);     // Read the entire file into the buffer. file.seekg(0, ios::beg); file.read(file_buf, file_size);
if(file) { fileData.append(file_buf);   ret = true; } else { std::cout << "error: only " << file.gcount() << " could be read"; fileData.append(file_buf); //ret = false; } file.close(); delete []file_buf; }
return ret;}
int main(){ string data; if(readFileToString("d:/Test.txt", data)) { cout<<"File data is:\r\n"<<data<<endl; } else { cout<<"Failed to open the file, please check the file path."<<endl; }
  cout << "size: " << data.size() << "\n";    cout << "length: " << data.length() << "\n";    cout << "capacity: " << data.capacity() << "\n";    cout << "max_size: " << data.max_size() << "\n";
getchar();}

运行结果：（为了方便显示，这里打开的是一个很小的文件。）读取文件内容并保存到string中

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

using namespace std;

bool readFileToString(string file_name, string& fileData)
{

    ifstream file(file_name.c_str(),  std::ifstream::binary);

    if(file)
    {
        // Calculate the file's size, and allocate a buffer of that size.
        file.seekg(0, file.end);
        const int file_size = file.tellg();
        char* file_buf = new char [file_size+1];
        //make sure the end tag \0 of string.
        memset(file_buf, 0, file_size+1);

        // Read the entire file into the buffer.
        file.seekg(0, ios::beg);
        file.read(file_buf, file_size);

        if(file)
        {
            fileData.append(file_buf);
        }
        else
        {
            std::cout << "error: only " <<  file.gcount() << " could be read";
            fileData.append(file_buf);
            return false;
        }
        file.close();
        delete []file_buf;
    }
    else
    {
        return false;
    }

    return true;
}

int main()
{
    string data;
    if(readFileToString("d:/Test.txt", data))
    {
        cout<<"File data is:\r\n"<<data<<endl;
    }
    else
    {
        cout<<"Failed to open the file, please check the file path."<<endl;
    }

    cout << "size: " <<  data.size() << "\n";
    cout << "length: " <<  data.length() << "\n";
    cout << "capacity: " <<  data.capacity() << "\n";
    cout << "max_size: " <<  data.max_size() << "\n";

    getchar();
}

The MIT license:

Permission is hereby granted, freeof charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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读取文件内容并保存到string中

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