# Uses a dictionary to implement a word count,
# so that the user can see which words
# occur the most in the book Moby-Dick.

# minimum number of occurrences needed to be printed
OCCURRENCES = 2000

def intro():
    print("This program displays the most")
    print("frequently occurring words from")
    print("the book Moby Dick.")
    print()

# Reads book and returns a dictionary of (word, count) pairs.
def count_all_words(file):
    # read the book into a dictionary
    word_counts = {}
    for word in file.read().lower().split():
        if word in word_counts:
            word_counts[word] += 1   # seen before
        else:
            word_counts[word] = 1    # never seen before
    return word_counts

# Displays top words that occur in the dictionary
# at least OCCURRENCES number of times.
def print_results(word_counts):
    for word, count in word_counts.items():
        if count > OCCURRENCES:
            print(word, "occurs", count, "times.")

def main():
    intro()
    with open("mobydick.txt") as file:
        word_counts = count_all_words(file)
        print_results(word_counts)

main()