fstream和stringstream之间的转换

#include <fstream> #include <sstream>     const char* filepath = "C:/test.txt";     ifstream in(filepath);     if(in.bad())     {         printf("open file '%d' failed!", filepath);         return;     }     stringstream ss;     ss << in.rdbuf();     string str(ss.str());     printf(str.c_str());          in.close();

这里再贴上用fopen()打开一个文件并写入二进制流的方法。

void RegexSearch::LoadStreamFromFile( char** buffer,const char* filepath ) {     FILE* pFile = NULL;     int err = ::fopen_s(&pFile, filepath, "rb");     if(0 != err)     {         printf("open file '%s' failed!", filepath);         return;     }     unsigned int length = 0;     int growSize = 512;     while(!feof(pFile))     {         char* temp = (char*)calloc(length + growSize, sizeof(char));         //将之前已读取的字节流拷贝到新的已扩容的动态数组中         memcpy( temp, *buffer, length );         if(*buffer)             free(*buffer);         *buffer = temp;         //每次读取固定大小growSize长度个字符，并拼接到*buffer指向的字符串尾部         fread((*buffer) + length, sizeof(char), growSize, pFile);         length += growSize;     }     fclose(pFile); }