/*s_temp point to the s string*/
for (s_temp = s; *s_temp != '\0'; s_temp++)
{
/*the move_tmp used for pattern loop*/
m_temp = s_temp;
/*the pattern string loop from head every time*/
for (t_temp = t; *t_temp == *m_temp; t_temp++, m_temp++);
/*if at the tail of the pattern string return s_tmp*/
if (*t_temp == '\0') return s_temp;