Question

Write a short C++ function that counts the number of vowels in a given character string.

Short answer

Define the function, loop through the string, check for vowels, count them, and return the count.

Step-by-step solution

- Function Definition

Start by defining the function. The function should take a character string as an input and return an integer representing the number of vowels in the string.

- Initialize Count Variable

Declare a variable to keep track of the number of vowels. Initialize this variable to 0.

- Loop Through String

Use a loop to iterate through each character in the string.

- Check for Vowels

Inside the loop, use an if statement to check if the current character is a vowel (`a`, `e`, `i`, `o`, `u` or their uppercase counterparts). If it is, increment the count variable.

- Return Count

After the loop finishes, return the count variable, which now holds the number of vowels in the string.

- Example Code

Here is the complete C++ function:```cppint countVowels(const std::string& str) { int count = 0; for(char c : str) { if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u' || c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U') { count++; } } return count;}```

Key concepts

C++ Programming

In this exercise, we will use C++ to create a function that counts vowels in a string. C++ is a powerful programming language known for its performance and flexibility. It is widely used for system/software development, game development, and in embedded systems.
To define a function in C++, you specify the return type, the function name, and any parameters it needs. For our vowel-counting function, `int` is the return type because we will return an integer. The function name will be `countVowels`, and it will take a `const std::string& str` as a parameter. The `const` keyword ensures the string is not modified.
Remember to include the necessary headers, like `` and ``, to use string functionalities.

String Manipulation

String manipulation involves performing operations on strings, like searching, replacing, and iterating over characters. In C++, strings are objects from the `std::string` class in the Standard Library.
To pass a string to our function, we use `const std::string&` to avoid copying the string, which is more efficient.
For our specific task, we will iterate through each character of the string to check if it is a vowel. C++ makes it easy to loop over strings using a range-based for loop.
This enables simplified syntax, making your code easier to read and write.

Character Iteration

Character iteration involves examining each character in a string one at a time. In C++, you can use a range-based for loop for this purpose. This type of loop looks like this: `for (char c : str)`. Here, `c` represents each character in the string `str`.
Inside this loop, we can perform actions or checks on each character. It's a clear and concise way to process strings in C++.
For example:
`for (char c : str) { if (isVowel(c)) { count++; } }`
This loop checks if each character is a vowel and increments our count variable if it is.

Conditional Statements

Conditional statements allow you to execute different blocks of code based on certain conditions. The `if` statement is the most basic one in C++. In our vowel-counting function, we use an `if` statement to check if the current character is a vowel.
Here's how we do it:
`if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u' || c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U')`
This condition uses the logical OR operator (`||`) to check if `c` matches any vowel, either lowercase or uppercase.
If the condition is true, we increment our count variable with `count++`. This ensures that our function correctly counts all vowels in the string.