Unions

Unions:-

          Structure data type is so defined that it is able to accept heterogeneous data type. Thus structure data type allows to pack together different types of data values as a single unit. Unions are also similar to structure data type except that the members are over laid one on top of another, so members of a union data type share the same memory.

          Unions obey the same syntactic rules as structures. We can access elements with either the dot operator (.) or right arrow operator (à). The major use of union in memory space utilization. Union would hold a value for one data type of the larger storage of their members.

          Ex-

                    #include<stdio.h>

                    #include<conio.h>

                    void main()

                    {

                          struct date

                            {

                                int day;

                                 int month;

                                int year;

                            };

                          union value

                          {

                                   int i;

                                  float f;

                                   struct date bdate;

                           };

                        union value x;

                           x.i=10;

                            x.f=-1456.45;

                            x.bdate.day=25;

                           x.bdate.month=7;

                           x.bdate.year=1972;

                   printf(“frist member%d\n”,x.i);

                   printf(“second member%f\n”,x.f);

                   printf(“structure:\n”);

                   printf(“%d%d%d\n”,x.bdate.day,x.bdate.month,x.bdate.year);

           }