# 
#  Overview
We can use **Objective C** to rename a datatype using the `typedef` fucnction.

The **`typedef` function** is used to assign the new name to the datatype. So that you can use a custom name for predefined long names of the datatypes. This will not only save time but also aids in having more understandable and easy-to-read code.

##
## Syntax
---
```
typedef unsigned char byte;
```
---
## Example


We declare three data types with the addition of `typedef` in the starting.


#import <Foundation/Foundation.h>

typedef char *String;
typedef int Dollars;
typedef unsigned long long ITS64;

int main() {
  NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
  String mybird = "Sparrow";
  String m = "hifza";
  Dollars yourdollar = 1000;
  ITS64 i = 18;
  // For Printing the values you can use NS Log and printf methods
  printf("%s\n", m);
  printf("%s\n", mybird);
  NSLog(@"Your value is %i", yourdollar);
  NSLog(@"Your value is %llu", i);
  [pool drain];
  return 0;
}

objective-c

## Explanation
* Line 1:  We import the Foundation framework that loads the base structure for Objective C programming.
* Lines 2–4: We define the data types with new names by using the `typedef` keyword. For `int`, we use Dollars and for unsigned long long, we use `ITS64`. 
This helps us from using such long names of data types again and again. 
* Lines 7–10: Inside the main function, we give the values against the variable names. 
We use the new names of the data types given at the start.
* Lines 11–14: We print the values of the variables `m`, `mybird`, `yourdollar`, and `i`. We use `NSLog` to display a message along with the value of the variable.
> **Note:** This function also allows the programmers to assign new names to the user-defined data types. For Instance, you can consider renaming a structure Drinks.

## Use `typedef` with `struct`

This allows us to use `Drink` only, instead of using `struct Drinks` again and again. 

#import <Foundation/Foundation.h>

typedef struct Drinks{
   NSString *Drink_name;
   NSString *Size;
   int drink_id;
} Drink;
 
int main() {
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
   Drink mydrink;
   mydrink.Drink_name = @"Strawberry Icecream Shake";
   mydrink.Size = @"Medium";
   mydrink.drink_id = 11;

   NSLog( @"Drink Name : %@\n", mydrink.Drink_name);
   NSLog( @"Drink Size : %@\n", mydrink.Size);
   NSLog( @"Drink # : %d\n", mydrink.drink_id);
   [pool drain];
   return 0;
}

objc.tar.gz

What is typedef in objective C?

The typedef function in Objective C renames datatypes for easier readability and code management.

What is typedef in objective C?

Overview

Syntax

Example

Explanation

Use typedef with struct

Explanation

Use `typedef` with `struct`