Basically, iostream is one of the CPP Stream used for reading and writing into a program with the help of cin and cout. Reading and writing into file can also be done using fstream standard library in files. fstream must be used as header file while doing input and output operations to a file along with iostream.

File pointers are used to set the position of the data as per the requirement. The positioning can be done using few streams. They are Some other functions used in fstream standard library are [c] //Declaring file using fstream fstream eg_file; //open file test.txt for read and write eg_file.open("splessons.txt"); //checking if file is opened if (!eg_file.is_open()) { cout << " Cannot open teh example file!" << endl; } //write information into file eg_file << "Hello, welcome to splessons " << endl << "You are reading C++ tutorial" << endl; //setting position of next extracted value eg_file.seekg(ios::beg); //read first 3 numbers from splessons.txt for (int i = 0; i != 3; ++i) { //diplaying the values which are read cout << (char)eg_file.get() << endl; } //taking the next character from file using get() char next = eg_file.get(); cout << "The next character is " << (char)next << endl; //reset position again eg_file.seekg(ios::beg); char* str = new char[50]; //copying first line into str eg_file.getline(str, 50); //first line cout << str << endl; //ignore next extracted character eg_file.ignore(); //without extracting it from file,showing the next character cout << "Peek " << (char) eg_file.peek() << endl; //get current position cout << "Current position is " << eg_file.tellg() << endl; //closing the file eg_file.close();[/c]

CPP Stream chapter draws out following important points.

• “fstream” is the header to do input/output operations in files.
• File pointers sets the data position.