Learn to read and write blocks of binary data, ideal for handling structures or arrays.
While functions like `fprintf` are great for text files, `fread()` and `fwrite()` are the preferred functions in C for reading and writing blocks of binary data. They are particularly efficient for handling non-textual data, such as images, audio, or program-specific data structures. These functions allow you to read or write a specified number of bytes directly from or to a file without any formatting. The `fwrite()` function is used to write data. Its signature is `fwrite(ptr, size, count, stream)`. Here, `ptr` is a pointer to the block of memory containing the data to be written, `size` is the size in bytes of each element to be written, `count` is the number of elements to write, and `stream` is the `FILE` pointer to the file. For example, you can use `fwrite` to write an entire structure variable or an array to a file in a single operation. The `fread()` function is the counterpart for reading data. Its signature is `fread(ptr, size, count, stream)`. It reads `count` elements, each of `size` bytes, from the `stream` and stores them in the block of memory pointed to by `ptr`. It returns the number of items successfully read, which can be less than `count` if an error occurs or the end of the file is reached. Because these functions work with raw bytes, they are much faster than formatted I/O functions for bulk data transfer. They are the standard way to save and load complex data structures to and from files.