vowel aS . a. Write a C program that keeps track of the frequency of occurrence of ea lines of text are typed at the keyboard. The end of the text should be signified hu entry of an EOF (see Section 5.3) marker (Ctrl z for DOS and Ctrl d for Unix). The output of your program should be a count of each vowel encountered in the input text. b. Add a function to the program written for Exercise 10a that displays a histogram of the number of each vowel encountered. For example, if your program detected the letter a five times, the letter e three times, the letter i two times, the letter o forur times, and the letter u 1 time, the histogram should appear as vowel. : |3?** 0 510 15