Question

Write the definition of a function that takes as input a char value and returns true if the character is uppercase; otherwise, it returns false.

Short answer

Define `isUpperCase(char c)` to return `true` if `c` is between 'A' and 'Z' ASCII values.

Step-by-step solution

Define the Function Header

Start by writing the function signature. In this case, we'll define a function `isUpperCase` which takes a single argument of type `char` and returns a `bool` indicating if the character is uppercase.

Check the Character's Case

Inside the function, we need to determine if the input character is uppercase. We can do this by checking if the character falls within the uppercase ASCII range, which is from 65 (A) to 90 (Z).

Return the Result

If the character's ASCII value is between 65 and 90, return `true`. Otherwise, return `false`. This can be achieved using a simple conditional statement.

Implementing the Function

Now, let's implement the function in C++: ```cpp bool isUpperCase(char c) { return (c >= 'A' && c <= 'Z'); } ```

Key concepts

Character Data Type

In C++, the character data type, represented as `char`, is used to store individual characters. Each `char` occupies 1 byte of memory, which is equivalent to 8 bits. With this storage capacity, `char` can represent 256 different values ranging from 0 to 255.

• Characters can be alphabetic letters, digits, punctuation marks, or control characters.
• Usually, `char` is used to represent symbols in the ASCII character set.
• In C++, characters are enclosed in single quotes, for instance, `'A'`, `'b'`, or `'1'`.

Understanding the `char` data type is crucial for processing text-based information. It helps in operations like case transformations, comparing characters, and more.

ASCII Values in C++

C++ uses the ASCII (American Standard Code for Information Interchange) character encoding standard to represent characters as numerical values.

• ASCII assigns a unique numerical value to each character, enabling computers to handle text effectively.
• For instance, the uppercase letter 'A' is represented by the ASCII value 65, while 'Z' is 90.
• This numeric representation allows us to perform operations like comparison and arithmetic on characters.

Using ASCII values, you can determine if a character is uppercase, lowercase, or a digit by checking its corresponding numerical range. This is a foundational concept for string and character manipulations.

Boolean Return Type

A Boolean return type in C++ is represented using the `bool` keyword. This type is fundamental for making decisions in programming, as it evaluates expressions that result in either `true` or `false`.

• The `bool` type occupies 1 byte in memory and is used in conditional statements.
• In C++, an expression evaluates to either `true` (non-zero or typically 1) or `false` (zero).
• Boolean expressions are crucial for flow control, such as loops and if-else structures.

By defining functions with a `bool` return type, programmers can succinctly indicate yes/no or on/off states, enhancing the readability and functionality of the code.

Conditional Statements in C++

Conditional statements in C++ allow the program to make decisions based on certain conditions. They direct the flow of execution depending on whether a specific condition is `true` or `false`.

• The most fundamental conditional statement is the `if` statement.
• Syntax: ```cpp if (condition) { // code to be executed if the condition is true } ```
• Conditional expressions often involve relational and logical operators (e.g., `==`, `!=`, `&&`, `||`).
• An `else` statement can be paired with an `if` to provide an alternative execution path.

Using conditional statements efficiently is key to creating dynamic and versatile programs. They ensure that different actions are taken based on varying inputs or states of the program.