Write a program that counts the total number of vowels in a sentence. Output the frequency of each vowel.

Character iteration is the process of sequentially moving through each character in a string. When counting vowels in a sentence, the program needs to examine every character to determine whether it's a vowel. This process typically involves using a loop structure, such as a for loop, to go through the sentence character by character.

For example, the pseudocode for iterating through a string could look like the following:

• For each character in the string
• Check if the character is a vowel
• If it is, perform some action (like incrementing a counter)

Each iteration allows the algorithm to handle the character, thus ensuring none are missed. It's like reading each letter of a sentence out loud - you go letter by letter, not skipping any. Consistency is key to ensure every vowel is accounted for accurately.

A frequency dictionary is a data structure used to keep track of how many times certain items occur. In the context of a vowel counting algorithm, the dictionary keys would be the vowel characters ('A', 'E', 'I', 'O', 'U', and their lowercase counterparts), and the values would be the number of times each vowel appears in the sentence.

By initializing the frequency dictionary with each vowel set to zero:

• A: 0
• E: 0
• I: 0
• O: 0
• U: 0

The algorithm can increment the count each time a vowel is encountered during the character iteration. This allows for efficient storage and retrieval of vowel occurrence data, making the process of counting and displaying each vowel's frequency straightforward and systematic.

Vowel identification is a fundamental part of the algorithm that distinguishes vowels from other characters in a sentence. The main challenge is to accurately determine whether any given character is a vowel. To achieve this, the program considers a predefined list of vowels: 'A', 'E', 'I', 'O', 'U' (and their lowercase forms).

During character iteration, each character is compared against this list. If there's a match, the algorithm recognizes the character as a vowel.

This process might look like:

• Check if the character is in the list ['A', 'E', 'I', 'O', 'U', 'a', 'e', 'i', 'o', 'u']
• If so, it's a vowel

By accurately identifying vowels, the algorithm can tally them correctly using the frequency dictionary. Such identification forms the basis of operations for many text processing algorithms, making understanding it crucial for anyone looking to work with natural language data.