Write a C program to capitalize the first character in each sentence from a given file. Assume a sentence ends with a period '.' To get the result, the execution of this program must be cooperated with the redirection feature in shell. [Note: please do not directly read a file in your program by calling function fread or read. Use only function getchar instead.] For the program in (a), how to run it and count the most frequent digit in file test2.txt? Please write down the command you may need to use in terminal of Unix. Assume the program in (a) has a file name count.c. Write another C program to count the most frequent digit in a file. To get the result, the execution of this program must be cooperated with the redirection feature in shell. [Note: please do not directly read a file in your program using function fread or read. Only use function getchar instead.]