The only difference is that you use an ifstream or fstream object instead of the cin object. While doing C++ programming, you write information to a file from your program using the stream insertion operator (>) just as you use that operator to input information from the keyboard. But it is always a good practice that a programmer should close all the opened files before program termination.įollowing is the standard syntax for close() function, which is a member of fstream, ifstream, and ofstream objects. When a C++ program terminates it automatically flushes all the streams, release all the allocated memory and close all the opened files. Similar way, you can open a file for reading and writing purpose as follows −Īfile.open("file.dat", ios::out | ios::in ) Outfile.open("file.dat", ios::out | ios::trunc ) For example if you want to open a file in write mode and want to truncate it in case that already exists, following will be the syntax − You can combine two or more of these values by ORing them together. If the file already exists, its contents will be truncated before opening the file. Open a file for output and move the read/write control to the end of the file.
All output to that file to be appended to the end. Here, the first argument specifies the name and location of the file to be opened and the second argument of the open() member function defines the mode in which the file should be opened. Void open(const char *filename, ios::openmode mode) And ifstream object is used to open a file for reading purpose only.įollowing is the standard syntax for open() function, which is a member of fstream, ifstream, and ofstream objects. Either ofstream or fstream object may be used to open a file for writing. Opening a FileĪ file must be opened before you can read from it or write to it. To perform file processing in C++, header files and must be included in your C++ source file. This data type represents the file stream generally, and has the capabilities of both ofstream and ifstream which means it can create files, write information to files, and read information from files.
This data type represents the input file stream and is used to read information from files. This data type represents the output file stream and is used to create files and to write information to files. This requires another standard C++ library called fstream, which defines three new data types − Sr.No This tutorial will teach you how to read and write from a file.
So far, we have been using the iostream standard library, which provides cin and cout methods for reading from standard input and writing to standard output respectively.
0 kommentar(er)
