Writing Bytes with ostream Member Function write

When writing the integer number to a file, instead of using the statement

which for a four-byte integer could print as few digits as one or as many as 11 (10 digits plus a sign, each requiring a single byte of storage), we can use the statement

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which always writes the binary version of the integer number’s four bytes (on a machine with four-byte integers). Function write treats its first argument as a group of bytes by viewing the object in memory as a const char *, which is a pointer to a byte. Starting from that location, function write outputs the number of bytes specified by its second argument—an integer of type size_t. As we’ll see, istream function read can subsequently be used to read the four bytes back into integer variable number.