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UNIONS IN C. Contents. Union Data Type Defining of Union Memory Space Allocation Example of Union Result Difference between Structures & Union. Union Data Type
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Contents • Union Data Type • Defining of Union • Memory Space Allocation • Example of Union • Result • Difference between Structures & Union
Union Data Type A union is a user defined data type like structure. The union groups logically related variables into a single unit. The union data type allocate the space equal to space need to hold the largest data member of union. The union allows different types of variable to share same space in memory. There is no other difference between structure and union than internal difference. The method to declare, use and access the union is same as structure. BACK
Defining of Union A union has to defined, before it can used. The syntax of UNION is: union union_name { data_type-variable_name; data_type-variable_name; …….. data_type-variable_name; };
Example of Union The union of Employee is declared as: union employee { int emp_id; char name[20]; float salary; char address[50]; int dept_no; int age; }; BACK
Memory Space Allocation 8000 emp_id, dept_no, age 8002 salary 8004 name 8022 address 8050 BACK
Example #include <stdio.h> #include <string.h> union student { char name[20]; char subject[20]; float percentage; }; main() { union student record1; union student record2; strcpy(record1.name, "Raju"); strcpy(record1.subject, "Maths"); record1.percentage = 86.50;
printf("Union record1 values example\n"); printf(" Name : %s \n", record1.name); printf(" Subject : %s \n", record1.subject); printf(" Percentage : %f \n\n", record1.percentage); printf("Union record2 values example\n"); strcpy(record2.name, "Mani"); printf(" Name : %s \n", record2.name); strcpy(record2.subject, "Physics"); printf(" Subject : %s \n", record2.subject); record2.percentage = 99.50; printf(" Percentage : %f \n", record2.percentage); getch(); } BACK
Result BACK
Below table will help you how to form a C union, declare a union, initializing and accessing the members of the union. BACK
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