说明：  此程序用于检测两个vector量有没有相同的片段，例如一个Vector是 ABBC 第二个ABC，此程序可以检测初有无BC 或者有无AB并由此可以随意检测内容并且返回相应的数值。
(This assignment asks students to write a program to search a character sequence pointed by a pointer in another character sequence. The namely for them namely are “obj” and “source”. If there exist the same sequence, it will return the pointer pointing to the found character. If more than one sequence is found in the source, the first character in the found sequence will be output on the screen. A char function that return the pointer will be used in the required form. )