[nFileSize]; infile.seekg(0, std::ios_base::beg); memset(pFileBytes, 0, nFileSize); //1、每次读取8K //do //{ // infile.read((char*)(pFileBytes + nTotalSize), 8192); // int nReadBytes = infile.gcount(); // if (nReadBytes > 0) nTotalSize += nReadBytes; //} while ...
void UsingifstreamReadJson() { std::ifstream fileHandle("F:/alarm.json", std::ifstream::in | std::ifstream::binary); Json::Reader reader(Json::Features::strictMode()); Json::Value root; if (NULL == reader.parse(fileHandle, root)) { fileHandle.close(); return; } fileHandle.close(...
std::ifstream fileHandle; int nFileLen = 0; fileHandle.open("E:/thriftserver/output/facealarmnew.txt"); fileHandle.seekg(0, std::ios::end); nFileLen = fileHandle.tellg(); fileHandle.seekg(0, std::ios::beg); char szFileBuf[4096] = { 0 }; fileHandle.read(szFileBuf, nFileLen)...
C++ 通过以下几个类支持文件的输入输出： ofstream: 写操作（输出）的文件类 (由ostream引申而来) ifst...
键盘输入的数据保存在缓冲区中，当要提取时，是从缓冲区中拿如果一次输入过多，会留在那儿慢慢用，如果...
ifstream f("a_text_file_of_unknown_origin"); string line; getline(f, line); if(!f.fail()) { // a non-empty line was read // BUT, there might be an '\r' at the end now. } 编辑 感谢Neil 指出 f.good() 不是我想要的。 !f.fail() 是我想要的。 我可以自己手动删除它(请参...
filename要打开文件的文件名 mode打开文件的方式 3.ifstream:: is_open 1boolis_open()const; 文件流对象与文件绑定,返回 true ,否则 false 。 4.ifstream:: close 1voidclose();//关闭文件流 5.ifstream:: rdbuf 1filebuf* rdbuf()const; 返回一个filebuf对象指针,(The pointer to the internal filebuf...
I would expect that the latter case has badbit set, but it’s not; net result is that only half of the file is processed with no indications that an error occurred. The implications seem pretty severe; e.g. when processing a file with std::ifstream on a nfs, where read ...
#include <fstream> #include <iostream> #include <string> int main() { std::string filename = "Test.b"; // prepare a file to read double d = 3.14; std::ofstream(filename, std::ios::binary) .write(reinterpret_cast<char*>(&d), sizeof d) << 123 << "abc"; // open file for...
(filename, std::ios::binary);if(!istrm.is_open())std::cout<<"打开 "<<filename<<" 失败\n";else{doubled;istrm.read(reinterpret_cast<char*>(&d), sizeof d);// 二进制输入intn;std::strings;if(istrm>>n>>s)// 文本输入std::cout<<"从文件读回:"<<d<<' '<<n<<' '<<s<...