so it was only the issue of std::string class, thanks i succeed with the following code. #include <iostream> #include <fstream> #include <cstring> using namespace std; class Data { public: char name[20]; int id; public: Data(){} Data(char *n,int id){strcpy(name,n);this->id=id;} }; int main() { Data objdata; //fstream file("c:\\\\test.txt",ios::out | ios::binary); fstream file("c:\\\\test.txt",ios::in | ios::binary); if(file.is\_open()) { //file.write((char\*)&objdata,sizeof(Data)); file.read((char\*)&objdata,sizeof(Data)); cout<<objdata.name<<objdata.id; cout<<"Success"; file.close(); } else { cout<<"Error"; } return 0; }

fstream::eof() - returns true if the 'eofbit' has been set by a previous i/o operation. fstream::read(s, n) - sets 'eofbit' if the End-of-File is reached before n characters have been read. The file has only 5 characters and the while loop will execute twice. In the first pass you try to read 5 bytes and it will be success. In the second pass read will fail and sets the 'eofbit'. Since you are not checking how many bytes read, you cout the old buffer contents again. This is the reason why you got "abcfabcf". The code can be changed to print "abcf" once, by checking the bytes read using fstream::gcount() as ................. if(file.is_open()) { //file.write(data,sizeof(data)); while(!file.eof()) { file.read(data,sizeof(data)); if(file.gcount()) cout<<data; } file.close(); } ..................

The problem is you can't read from a not exitsting file, I suppose. Your bit mask works if the file do exist. On the other hand, if the file does not exist you should use the ios::out | ios::binary mask. :) If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile. This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke [My articles]