What are variables?

Variables are named storage locations in a computer's memory that hold values or data. They allow programmers to store, manipulate, and retrieve data during program execution. Variables have a data type that determines the kind of data they can hold, such as integers, floating-point numbers, characters, or custom-defined types.

How to declare one?

To declare a variable in C++:

Syntax:

<variable_name>;

Example:

int age;

In this example, ‘age’ is the variable name, and ‘int’ is the data type, indicating that the variable can hold integer values.

What is garbage value?

A garbage value refers to the value that is stored in a variable when it is created without being explicitly assigned a value. It is an unpredictable or random value that is leftover from the previous usage of the memory location. Garbage values can cause unexpected behavior and should be avoided by ensuring variables are initialized before use.

What is initialization and how to do it?

Initialization is the process of assigning an initial value to a variable at the time of declaration. It ensures that the variable starts with a well-defined value instead of containing a garbage value. Initialization can be done using an assignment operator (‘=‘) followed by the initial value.

Here's an example of variable initialization in C++:

int age = 25;

In this case, the variable ‘age’ is declared and initialized with the value 25.

What is memory address?

A memory address is a unique identifier that represents the location of a specific byte or group of bytes in the computer's memory. Every variable stored in memory has a unique address associated with it. Memory addresses are typically expressed as hexadecimal numbers.

In C++, you can retrieve the memory address of a variable using the address-of operator (‘&’). For example:

int number = 42;

int* ptr = &number; // ‘ptr’ holds the memory address of ‘number’

In this example, ‘&number’ retrieves the memory address of the variable ‘number’. The address is then stored in the pointer variable ‘ptr’, which has the type ‘int*’ (pointer to an integer).

Memory addresses are often used when working with pointers, dynamic memory allocation, and accessing or manipulating data indirectly through memory addresses.