文字祖玛游戏
需求如下：
1).程序通过控制台输出一个字符串，由A、B、C、D、E五个字母组成，例如：ACBEEBBAD。
2).用户输入一个字符，只能是A、B、C、D、E其中之一，然后再输入一个要插入的位置。
3).程序会将这个字符插入到字符串的指定位置前（第一个字符位置为0，第二个字符位置为1，依此类推），然后消除连续出现的三个相同的字符，直到没有连续三个相同的字符为止。
（本人的期末考试题）(Text Zuma game
The requirements are as follows:
1). The program outputs a string through the console, which is composed of five letters, such as A, B, C, D and E, for example: ACBEEBBAD.
2) the user enters a character, which can only be one of A, B, C, D and E, and then enter a location to insert.
3). The program inserts this character into the specified position of the string (the first character is 0, the second character position is 1, and so on), and then eliminates the consecutive three identical characters until there are no consecutive three identical characters.
(my final exam))