1. String array storage, is employed to establish two string String1 and String2, output two strings,
2. Add String2 head n a string to the end of String1, output, 3. Search string String3 position in the string String1, if String3 does not exist in String1, inserting String3 m position in String1, output,
4. For arbitrary string SUBSTR and delete the substring, 5. The string word number;