I need help with programming this in C please :)

1.2 anagram: String operations II Write a program anagram that prints all the letters in its input, sorted alphabetically. This can be useful for finding anagrams, as anagrams will produce identical output. anagram receives a single argument containing a string. Its output will contain the same letters as the argument, converted to lower-case and sorted alphabetically. Non-letter characters, such as whitespace, punctuation, and digits, will be ignored. Usage $ ./anagram 'genuine class' aceegilnnssu $ ./anagram 'Alec Guinness' aceegilnnssu $ ./anagram 'The quick brown fox jumps over the lazy dog.' abcdeeefghhijklmnoooopqrrsttuuvwxyz Notes You are free to use whatever algorithms you find convenient, and do not need to maximize efficiency. If you want to challenge yourself, find an algorithm that will sort the letters in linear time using a fixed number of local variables and no heap allocation