Defining New Data Types in C Language

Defining New Data Types

typedef can also be used with structures. The following creates a new type agun which is of type struct gun and can be initialised as usual:

              typedef struct gun

                            {

                            char name[50];

                            int magazinesize;

                            float calibre;

                            } agun;

               agun arnies={"Uzi",30,7};

Here gun still acts as a tag to the struct and is optional. Indeed since we have defined a new data type it is not really of much use, agun is the new data type. arnies is a variable of type agun which is a structure.

C also allows arrays of structures:

              typedef struct gun

                            {

                            char name[50];

                            int magazinesize;

                            float calibre;

                            } agun;

              agun arniesguns[1000];

This gives arniesguns a 1000 guns. This may be used in the following way:

          arniesguns[50].calibre=100;

gives Arnie's gun number 50 a calibre of 100mm, and:

          itscalibre=arniesguns[0].calibre;

assigns the calibre of Arnie's first gun to itscalibre.