子串查询函数strstr

/************************
 * Project Name	:	String Operation Functions
 * Module Name	:	Strstr.c
 * Create	:	2010-04-24(Sat)
 * Update	:	2010-04-24(Sat)
 * Copyright	:	Micheal Zhong
 * Reference	:	
 ************************/

#include<stdio.h>

int strstr( char *master, char *slave )
{
	char *m = master;
	char *s = slave;
	int count = 0;
	int temp = 0;
	while( *m != '/0' )//go to the tail of the master
	{
		while( *m != '/0' && *m != *s )
		//find the first char of slave in master
		{
			m++;
			count++;//count addition follows m
		}
		if( m == '/0' )
		//do not exist the first char of slave in master
			printf("DO NOT EXIST! CUP!/n");
		else temp = count;
		//exist the first char of slave in master
		//save its position to temp
		while( *m == *s && *s != '/0' && *m != '/0' )
		//compare slave and master until m != s
		//or get the end of master or slave
		{
			m++;
			count++;//count addition follows m
			s++;
		}
		if( *s == '/0' )
		//get the end of slave
		//which means slave exists in master
		{
			return temp;
			//output the position of the slave's head in master
			if( *m == '/0' )
			//get the end of master
				exit(0);
			else s = slave;
			//maybe slave appears more than one time in master
		}
		else if( *m == '/0' )//get the end of slave, then halt
		{
			printf( "DO NOT EXIST! CUP!/n" );
			exit(0);
		}
		else if( *m != *s )
		//The slave's head is similar to the master's substring
		//but do not match
		{
			s = slave;
			m = master + temp + 1;
			count = temp + 1;
		}
	}
}