//PAC: things with strings
//jleblanc: 2.27.06

/*Along the way, investigate the library "strings.h", as
the functions there could be quite interesting.  For
example, write a function that determines whether a
string is a candidate e-mail address ... or html file
... or txt file.

In addition, consider how you can create a new version
of the queue program, such that the program handles
strings rather than characters.*/

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

//AN email would be:
// _@_._ where last space either: edu, com, net, org, gov, .... But that is not safe
int is_email(char word[]);

void main()
{
	char word[50];
	
	//char *a, *d;
	char word1[]="jleblanc@nyu.edu";
	char word2[]="jleblanc.htm";
	char word3[]="jleblanc.html";
	char word4[]="jlebl@anc@nyu.ed.u";//A problem kind of function

	printf("enter a word: ");
	scanf("%s", word);

	printf("\n%s\n\n", word);

	printf("\n%d\n", is_email(word1));
	printf("\n%d\n", is_email(word2));
	printf("\n%d\n", is_email(word3));
	printf("\n%d\n\n", is_email(word4));

	printf("\n%d\n", is_htm(word1));
	printf("\n%d\n", is_htm(word2));
	printf("\n%d\n", is_htm(word3));
	printf("\n%d\n\n", is_htm(word4));

}

//Very Crude Function
int is_email(char word[])
{
	int is_it=-1;
	char *a, *d;
	a=strchr(word, '@');
	if(a!=NULL)
		{d=strchr(a, '.');}

	if(a!=NULL && d!=NULL)
	{
		is_it=1;
	}

	return is_it;
}

//Very Crude Function
//This might pick up html pages too
int is_htm(char word[])
{
	int is_it=-1;
	char *h;
	h=strstr(word, ".htm");

	if(h!=NULL)
	{
		is_it=1;
	}

	return is_it;
}

/*
2.14.9 strchr

Declaration:

    char *strchr(const char *str, int c); 

Searches for the first occurrence of the character c (an unsigned char) in the string pointed to by the argument str. 
The terminating null character is considered to be part of the string.

Returns a pointer pointing to the first matching character, or null if no match was found.
*/

/*2.14.21 strstr

Declaration:

    char *strstr(const char *str1, const char *str2); 

Finds the first occurrence of the entire string str2 (not including the terminating null character) which appears in the string str1.

Returns a pointer to the first occurrence of str2 in str1. If no match was found, then a null pointer is returned. If str2 points to a string
 of zero length, then the argument str1 is returned
*/