Creating a Container Application

	Chapter 18 - Complete I/O in C++
	Visual C++ 6: The Complete Reference
	Chris H. Pappas and William H. Murray, III

Copyright 1998 The McGraw-Hill Companies

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	The memset( ) Function

	The memset( ) function can be used to initialize a dynamically allocated byte, or bytes, to a specific character. The prototype for memset( ) looks like this:

	void *memset(void *dest, int cchar, size_t count);

	Once the memset( ) function is called, dest points to count bytes of memory initialized to the character cchar. The following example program demonstrates a dynamic structure declaration:

	// //  memset.cpp //  C++ program demonstrating the function memset( ), //  which can initialize dynamically allocated memory. //  Copyright (c) Chris H. Pappas and William H. Murray, 1998 // #include <iostream.h> #include <memory.h> struct keybits {  unsigned char rshift, lshift,  ctrl,   alt,                scroll, numlock, caplock, insert; };

	void main(void) {  keybits *pstkinitialized;  pstkinitialized = new keybits;  memset(pstkinitialized, 0, sizeof(keybits)); }

	Because of the memset( ) function, the dynamically allocated structure pointed to by pstkinitialized contains all zeros. The call to the function memset( ) also used the sizeof( ) operator instead of hardwiring the statement to a “magic number.” The use of sizeof( ) allows the algorithm to automatically adjust to the size of any object passed to it. Remember, too, that C++ does not require the struct keyword to precede a structure tag field (keybits) when defining structure variables, as is the case with pstkinitialized.

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