C Language Basic to Advance Course > Derived Datatypes

Union in C Programming

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In the C programming language, a union is a user-defined datatype. It is a memory region that contains a collection of variables of various datatypes. We can define a union with numerous members, but only one member can contain a value at any given time. Memory is saved by using C unions.

All members of a union have access to the same memory location. In the C programme below, for example, both x and y have the same position. We can see how changes in x are mirrored in y when we adjust x. #include stdio.h>/ Structures and declarations of union are the same thing.

The most typical purpose of a union is to allow various data types to access a single location, such as hardware input/output access, bitfield and word sharing, or type punning. Low-level polymorphism can also be found in unions.

When we define the union, we discover that it is defined in the same way that the structure is defined, with the exception that the union data type is specified using the union keyword, whereas the structure is defined using the struct keyword.

When we define a union, the memory allocated for a union variable of the type is the same as the memory required for the union's largest member, and other members share this memory space. "char arr[8]" is the largest member in the example above. As a result, the size of the union test is 8 bytes.

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  1. Introduction to C Programming
    24m 32s
  2. How to use LearnVern
    3m 20s
  3. Assignment : Introduction to C
    3m 17s

  1. Setting up C Environment
    17m 24s
  2. First Program in C
    25m 16s
  3. Assignment : Setting up C & First Program on C
    3m 50s

  1. Basic Syntax
    21m 44s
  2. Data Types in C Programming
    26m 19s
  3. Assignment : Structure of C
    7m 38s
  4. Variables in C Programming
    20m 35s
  5. Storage Classes in C Programming
    28m 23s
  6. printf() and scanf() Functions
    22m 56s
  7. Constants in C Programming
    18m 8s

  1. Operators in C Programming
    23m 18s
  2. Assignment : Operators in C
    3m 20s

  1. Decision Making- If Statement, If-else Statement
    19m 5s
  2. Decision Making - Nested If, Switch Statement, Nested Switch Statement
    26m 7s
  3. Entry Contolled Loops - For Loop, While Loop
    29m 25s
  4. Exit Controlled Loops - Do While Loop, Nested Loop
    21m 9s
  5. Break, Continue and Goto Statement
    14m 54s
  6. Assignment : Decision making and Flow Control
    9m 4s

  1. Introduction to User Defined Functions
    9m 28s
  2. User Defined Functions -Function Definition, Function Declaration and Function Call
    20m 55s
  3. User Defined Functions - Functions and Parameters
    19m 39s
  4. User Defined Functions- Types of Parameters
    20m 18s
  5. Scope of a Variable
    8m 3s
  6. Assignment : Working with User Defined Functions 1
    5m 24s
  7. Assignment : Working with User Defined Functions 2
    14m 45s

  1. Declaration & Initialization of Arrays
    17m 30s
  2. Accessing Array Elements
    12m 33s
  3. Types of Arrays
    7m 27s
  4. 2D Arrays
    11m
  5. Multidimensional Arrays
    25m 9s
  6. Introduction to Pointers
    16m 36s
  7. Pointers with Functions
    34m 18s
  8. Pointer Types: Null Pointer, Wide Pointer, Void Pointer
    24m 3s
  9. Pointer Arithmetic
    23m 28s
  10. Array of Pointers
    9m 58s
  11. Working with Strings
    17m 10s
  12. Introduction to Structures
    9m 47s
  13. Basic Structure Example
    10m 32s
  14. Nested Structures, Array of Structures
    27m 24s
  15. Union in C Programming
    12m 27s

  1. Typedef Function in C Programming
    10m 7s
  2. Assignment : Typedef Function
    2m 57s

  1. Overview of File Handling
    15m 2s
  2. Reading and Writing to Files
    16m 45s
  3. Assignment : File Handling in C
    7m 14s
  4. Basic File Handling
    13m 2s
  5. Bit Fields
    23m 17s
  6. File Input/Output Functions -I
    6m 16s
  7. File Input/Output Functions -II
    34m 48s

  1. Preprocessors and Header Files
    8m 29s
  2. Assignment : Preprocessors and Header Files
    3m 14s

  1. Type Casting
    8m 24s
  2. Assignment : Type Casting
    2m 37s

  1. Error Solving in C
    23m 7s
  2. Assignment : Error Solving in C
    2m 41s

  1. Recursive Functions in C
    14m 53s
  2. Assignment : Recursive Functions
    3m 5s

  1. Variable Arguments in User Defined Functioncs
    20m 2s
  2. Assignment : Variable Arguments in User Defined Functions
    3m 14s

  1. Memory Management
    11m 34s
  2. Assignment : Memory Management
    2m 58s

  1. Command Line Arguments
    9m 12s
  2. Assignment : Command Line Arguments
    2m 28s

  1. Inbuilt Library Functions- Math.h Library
    21m 39s
  2. Inbuilt Library Functions- String.h Library, Time.h Library
    33m 58s
  3. Assignment : C Programming Libraries
    4m 31s

  1. Running and Debugging programs in C
    19m 18s
  2. Assignment : Running and Debugging Programs
    3m 41s

  1. Compilation and Execution
    15m 53s
  2. Assignment : Compilation and Execution
    2m 59s

  1. Advanced C Features: Macros
    9m 8s
  2. Advanced C Features: Linked List
    12m 28s
  3. Assignment : Macros and Linked List
    3m 19s

  1. Printing a String
    11m 4s
  2. Swap 2 Numbers
    24m 11s
  3. Making a Calculator
    18m 4s
  4. Printing Patterns
    35m 43s
  5. Prime Check
    19m 56s
  6. Palindrome Check
    18m 49s
  7. Join 2 Strings
    8m 21s
  8. Reverse a string
    14m 29s
  9. Matrix Addition
    14m 59s
  10. Printing Array Elements and Addresses using Pointers
    18m 57s
  11. Structure for Student Data
    12m 14s
  12. Read and Write Data in a File
    9m 4s

  1. Course Summary
    11m 7s

  1. Interview Question
    30m 24s

  1. Career Guideline
    2m 48s
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