/*// ********************************************************************** //
// ** This file was downloaded from Jeff Heaton's Source Code Examples ** //
// **                      www.heat-on.com/source                      ** //
// ********************************************************************** //
// Copyright 1999 by Jeff Heaton
// ********************************************************************** //
// Permission is granted for royaltyfree use in compiled form.  No 
// additional licensing is required.  This code may not be distributed 
// in source form without written premission by Jeff Heaton.  Generally
// I will grant it.  Just ask first. //
// Basically I do not care how you distribute this code in compiled form.
// But if your going to publish my source code somewhere I'd like to hear
// about it first.
// ********************************************************************** //
// AddZeros V1.0// Written 1/22/1999 by Jeff Heaton//
// AddZeros is a handy function to add leading zeros to C string.  This 
// is very useful when you are storing some sort of a serial number in
// a C based string.  This function can handle ANY length string so long 
// as the input string is large enough to hold the number of zeros ask for
*/

#include <string.h>
#include <stdio.h>


/*
// Function Name: AddZeros
// Parameters:
//		str - Input string to add zeros to
//		zeros - How many leading zeros to add
// Returns:
//		Nothing.
// Purpose:
//		This function will modify str so that it contains the specified number
//	leading zeros.
// Author
//		Jeff Heaton
*/
void AddZeros(char *str,int zeros)
{
	char *source,*dest;

	if(strlen(str)>=zeros)
		return; /* Just the number is bigger than how many zeros you want */

	dest=str+zeros-1;
	source=str+strlen(str)-1;

	while(source>=str) /* Move the org string to the right */
		*(dest--)=*(source--);

	while(dest>=str)/* Fill in with zeros */
		*(dest--)='0';

	*(str+zeros)=0;/* Nul terminate the string */
}

void main(void)
{
	char str[80];
	int zeros;

	printf("\nPlease enter a number>");
	scanf("%s",str);
	printf("\nHow many leading zeros do you want>");
	scanf("%d",&zeros);
	AddZeros(str,zeros);
	printf("Here it is: %s\n",str);
	gets(str);
}