Typedef in C Language

In C language, typedef is a keyword used to give a new name to an existing data type, allowing you to create an alias for that type. This can be useful for making code more readable and for abstracting away implementation details.

The syntax for a typedef declaration is:

typedef <existing_data_type> <new_type_name>;

For example, you can create a new name for the int data type like this:

typedef int my_int;

After this declaration, my_int can be used as a new name for the int data type. For example, you can declare a variable of type my_int like this:

my_int x = 42;

This is equivalent to declaring a variable of type int:

int x = 42;

You can also use typedef to create new names for more complex data types, such as structures or pointers. For example, you can create a new name for a structure like this:

typedef struct {
  int x;
  int y;
} point;

After this declaration, point can be used as a new name for the structure. For example, you can declare a variable of type point like this:

point p = {1, 2};

This is equivalent to declaring a variable of the original structure type:

struct {
  int x;
  int y;
} p = {1, 2};

Using typedef can make code more readable by creating more descriptive type names. For example, instead of declaring a variable of type int *, you can create a new name for that type like this:

typedef int *int_ptr;

After this declaration, you can declare a variable of type int_ptr like this:

int_ptr p = &x;

This is equivalent to declaring a variable of type int *:

int *p = &x;