//  模拟库函数strstr#include 
     
      #include 
      
       const char* my_strstr(const char *parent, const char *child){	const char *pgo = parent;	const char *cgo = child;	const char *pgos = parent;	assert(parent != NULL && child != NULL);	if (!*child)	{		return NULL;	}	while (*pgo)	{		pgo = pgos;		cgo = child;		while (*pgo == *cgo && *pgo && *cgo)		{			pgo++;			cgo++;		}		if (*cgo == '\0')			return pgos;		pgos++;	}	return NULL;}int main(){	printf("%s\n", my_strstr("hhhww", "hhww"));	printf("%s\n", my_strstr("zhaoyaqian","aoya"));	printf("%s\n", my_strstr("abc", "aefg"));	return 0;}