In this tutorial you will learn about the C typedef and its application with practical example.
In C programming language typedef ( type definition ) is a keyword that allows us to create an alias for existing data types. Once, we have created a type definition, then we can declare a variable using the alias we created. This alias is equivalent to the data type for which it is created. Remember that, in addition to the type definition or alias we are always free to use the original keyword to define variables of any data type.
Syntax:
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typedef existing_type new_name; |
It is easy to create the alias, put the typedef keyword followed by the existing type name and the new name for that type.
Let’s take look at the example below:
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typedef int my_type; my_type var1, var2, var3; |
We have created the alias for integer data type as “my_type”, now my_type behaves the same as an integer.
Advantages of C Typedef
- It makes the program more portable.
- typedef makes complex declarations easier to understand.
typedef with a struct
Take a look at below structure declaration
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struct student{ int id; char *name; float percentage; }; struct student a,b; |
As we can see we have to include keyword struct every time you declare a new variable, but if we use typedef then the declaration will be as easy as below
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typedef struct{ int id; char *name; float percentage; }student; student a,b; |
this way c typedef makes your declaration simpler.
C Typedef with Union
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typedef union{ int id; char *name; float percentage; }student; student a,b; |
typedef with enum
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typedef enum {sun, mon, tue, wed, thu, fri, sat} weekday; weekday day1; |
