C programming must be compiled with gcc -Wall

1. (60 points) Joe wants a way to encode his notes he passes in class so his teacher cannot read them. Write a program that encodes a sentence by switching every alphabetical letter (lower case or upper case) with alphabetical position i with the letter with alphabetical position 25 i. For example, letter a is at position 0 and after encoding it becomes letter z (position 25). Letter m is at position 12, it becomes letter n (25 12 = 13) after encoding. For example,

Input: at the cafeteria Output: zg gsv xzuvgvirz 

Your program should include the following function:

void convert(char *s1, char *s2); The function expects s1 to point to a string containing the input as a string and stores

the output to the string pointed by s2.

1) Name your program notes.c. 2) Assume input is no longer than 1000 characters. 3) The convert function should use pointer arithmetic (instead of array

subscripting). In other words, eliminate the loop index variables and all use of

the [] operator in the function.

4) To read a line of text, use the read_line function (the pointer version) in the lecture notes.