Lec14: bool and void Data Types in C++ | C++ Tutorials for beginners

Summary

In this video, the presenter discusses the `bool` and `void` data types in C++. The `bool` data type is used to store Boolean values (`true` or `false`), and its practical use in conditional statements is explored. The `void` data type, representing 'nothing,' is examined through its three main applications: as a function return type, a parameter type, and for creating generic pointers. The video also provides code examples to demonstrate how both `bool` and `void` are used in real C++ programs, highlighting their importance for clear, efficient programming.

Takeaways

• 😀 Bool is a built-in data type in C++ that can store two values: true or false. True is represented as 1, and false as 0.
• 😀 In C99, bool was introduced in C, and it is also available in C++ as a native data type.
• 😀 Using bool in conditional statements (like if-else) improves readability compared to using 1 or 0 for true or false.
• 😀 The size of a bool in C++ is typically 1 byte, but it can vary depending on the compiler or platform.
• 😀 The void data type represents 'nothing' and is typically used as a return type for functions that don't return any value.
• 😀 The void data type can also be used to indicate that a function doesn't accept any parameters.
• 😀 A void pointer is a universal pointer type that can point to any data type, and it needs to be typecasted before dereferencing.
• 😀 In C++, you cannot declare a variable of type void, as it has no associated memory size.
• 😀 When using void pointers, typecasting is required before dereferencing, as the pointer doesn’t know the type of the data it points to.
• 😀 When working with bool, any non-zero value is considered 'true', and only zero is considered 'false'.

Q & A

What are the two data types being discussed in the video?

The video discusses the 'bool' and 'void' data types in C++.

Why was the bool data type not available in C until C99?

The bool data type was not available in C before C99, and it was only introduced in C99 as part of the standard. C++ had already included it before that.

What values can a bool variable hold in C++?

A bool variable in C++ can hold two values: 'true' or 'false'. True is represented by 1, and false is represented by 0.

What is the advantage of using 'true' and 'false' in C++ instead of 1 and 0?

Using 'true' and 'false' increases the readability and understanding of code, as they are more intuitive compared to using 1 for true and 0 for false.

How can you use bool values in conditional statements in C++?

You can use bool values directly in conditional statements such as if-else. For example, instead of using 1 or 0, you can write 'true' or 'false' for better readability.

Can a variable be directly declared with the void data type in C++?

No, you cannot declare a variable with the void data type in C++, as void means 'nothing' and doesn't allocate memory for any data.

What is a void pointer, and how is it used in C++?

A void pointer is a generic pointer that can store the address of any data type. It can be typecasted to other pointer types (e.g., int pointer, float pointer) as needed.

What are the three main uses of the void data type in C++?

The three main uses of the void data type in C++ are: as the return type of a function that doesn't return a value, as the argument type in a function that doesn't accept arguments, and for creating void pointers.

What happens when you try to dereference a void pointer without casting it?

If you try to dereference a void pointer without casting it, you will get an error because the compiler doesn't know the data type of the pointer, and it cannot determine how many bytes to access.

What is the default size of the bool data type in C++, and how can you check it?

The default size of the bool data type in C++ is typically 1 byte. You can check the size of a bool using the 'sizeof' operator, for example, 'sizeof(bool)' will return 1.