Please solve it the easy and simple way IN C LANGUAGE. Keep it understandable and simple. Do not include extra difficult libraries etc. This is the assignment for a 2nd grade structured programming course.

Letters in a string: Write a program that asks the user to input a lowercase string, and outputs the unique characters that make up the string arranged in alphabetical order. For instance if the string is abracadabra, the output should be a,b,c,d,r Assume there are no spaces in the string. The integer code for the character 'a' is 97. C:\Users\win8\Desktop\3.exe Input string: abracadabra The letters of the string are: a, b, c, d, r Process exited, after 3.558 seconds with return value o Press any key to continue