You need patient to solve this problem. There are some important ponts.

�      Your first task is to reverse the input string in the case of encoded massage

�      Every normal message have alphabet and punctuation and no numbers.

�      Every encoded message consists numbers only.

�      Those alphabet whose ASCII value is three digit, all will start with 1 and remaning will be started with other than 1.

The algorithm is as follows.

1.      Read ->str

2.      if str[0] is a  digit

3.                   then decode str

4.                   else encode str

Algorithm of decode

1.      Reverse str

2.      l <- length str

3.      for i =0 to l

4.                   if str[i] = 1

5.                   then get three character and make it integer a.

6.                   i = i+3;

7.                   else get two character and make integer a.

8.                  i = i+2;

9.                   print character represented by a.

Algorithm of encode

1.       l <- length str

2.      for i =0 to l

3.                   strtmp[i] = ascii str[i]

4.      reverse str