Exercise Description Write a search program called search.c that runs as follows ./search Your program reads the given text file input_file, which contains a string on each line, and displays the characters that occur more than a given threshold . You can assume the following: (1) there will be only one word on each line, (2) the word will contain only lower case letters, and (3) the word will have at most 10 letters. For example, given the following input file, input.txt : cat mouse bat hat the following are three scenarios that would happen if you run your program: nadiug12:-> /search input.txt 1 a appears 3 times t appears 3 times nadi@ug12:-> ./search input.txt 0 a appears 3 times b appears i time c appears i time e appears i time h appears i time m appears i time o appears i time s appears i time t appears 3 times u appears i time nadi@ug12:-> . /search input.txt 3 There are no letters that exceed this threshold Your program must check that the correct number of program arguments has been passed. For example, running the program with a missing argument should produce the following message to stderr : nadi@ug12:-> ./search input.txt Usage: /search Your program must check if the input file exists. If the input file does not exist, the program must exit. For example, running the program with a file that does not exist should produce the following message to stderr : nadi@ug12:-> ./search nonexistent_file.txt 5 Error: cannot find nonexistent_file.txt Your program must also close the file stream before exiting. Your program must use an array to store the frequency of the letters of the alphabet. You can safely assume that you need to only handle 26 lower-case letters. Your program must contain a Makefile that compiles your program into an executable called search. Your program must compile without warnings or errors. Your Makefile must have a clean target. Otherwise, you will get a 0 for this exercise. Hint: google the function atoi to see how you can treat the passed threshold as an integer