In C language, typedef is a keyword used to create an alias or a new name for an existing data type. It does not create a new data type but makes code easier to read and maintain. typedef is commonly used to simplify complex declarations, improve code readability, or to give a meaningful name to types.

Syntax of typedef:

typedef existing_type new_name;

Example:

typedef unsigned int uint;

In this example, uint becomes an alias for unsigned int. Instead of writing unsigned int everywhere in the code, you can just use uint.

Use Cases:

1. Simple Type Aliases:

   typedef char* string;
   

   Here, string is an alias for char*.

2. Complex Struct Definitions: Typedef is particularly useful when working with structures:

   struct Person {
       char name[50];
       int age;
   };
   
   typedef struct Person Person;
   
   Person p1; // Now you can declare a variable without needing "struct" keyword.
   

3. Function Pointer: Typedef can also simplify function pointer declarations:

   typedef void (*func_ptr)(int, int);
   

   Instead of repeatedly writing void (*)(int, int), you can just use func_ptr.

Benefits of Using typedef:

1. Readability: Improves the readability of code, especially for complex types.
2. Portability: You can easily change types in one place if you decide to update data types later.
3. Abstraction: Makes the underlying data type abstract, allowing you to change it without affecting code that uses it.

Example of typedef with struct:

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

Point p1; // instead of "struct Point p1"
p1.x = 10;
p1.y = 20;

In this example, the typedef allows you to declare a Point without using the struct keyword every time.