In this program, a pointer variable ptr and normal variable d of type structure Distance is defined.

The address of variable d is stored to pointer variable, that is, ptr is pointing to variable d. Then, the member function of variable d is accessed using pointer.

Notes:

🔘Since pointer ptr is pointing to variable d in this program, (*ptr).inch and d.inch are equivalent. Similarly, (*ptr).feet and d.feet are equivalent.
🔘However, if we are using pointers, it is far more preferable to access struct members using the -> operator, since the . operator has a higher precedence than the * operator.

Hence, we enclose *ptr in brackets when using (*ptr).inch. Because of this, it is easier to make mistakes if both operators are used together in a single code.

ptr->feet is same as (*ptr).feet
ptr->inch is same as (*ptr).inc

C++ Enumeration
In this article, you will learn to work with enumeration (enum). Also, you will learn where enums are commonly used in C++ programming.

An enumeration is a user-defined data type that consists of integral constants. To define an enumeration, keyword enum is used.

Here, the name of the enumeration is season.

And, spring, summer and winter are values of type season.

By default, spring is 0, summer is 1 and so on. You can change the default value of an enum element during declaration (if necessary).

Enumerated Type Declaration
When you create an enumerated type, only blueprint for the variable is created. Here's how you can create variables of enum type.

enum boolean { false, true };

// inside function
enum boolean check;

Here, a variable check of type enum boolean is created.

Here is another way to declare same check variable using different syntax.

enum boolean
{
false, true
} check;

Output

Day 4

Output

Summer = 4

Why enums are used in C++ programming?
An enum variable takes only one value out of many possible values. Example to demonstrate it,

Output

Size of enum variable 4 bytes.

It's because the size of an integer is 4 bytes.;

This makes enum a good choice to work with flags.

You can accomplish the same task using C++ structures. However, working with enums gives you efficiency along with flexibility.

How to use enums for flags?
Let us take an example,

enum designFlags {
ITALICS = 1,
BOLD = 2,
UNDERLINE = 4
} button;
Suppose you are designing a button for Windows application. You can set flags ITALICS, BOLD and UNDERLINE to work with text.