C Exercises: Show a pointer to union

Last update on March 19 2025 12:41:00 (UTC/GMT +8 hours)

19. Pointer to a Union

Write a program in C to show a pointer to a union.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>

// Defining a union to hold employee address details
union empAdd {
    char *ename;    // Employee name (string pointer)
    char stname[20]; // Street name (array of characters)
    int pincode;    // Pincode (integer)
};

// Main function
int main() {
    // Displaying the purpose of the program
    printf("\n\n Pointer : Show a pointer to union :\n");
    printf("----------------------------------------\n");

    union empAdd employee, *pt; // Declaring union variables

    // Assigning a string up to the null character ('\0') to the union member
    employee.ename = "John Mc\0Donald"; // Assigning the string up to null character

    pt = &employee; // Storing the address of the union variable in a pointer

    // Printing the content of the union member using pointer to union
    printf(" %s %s\n\n", pt->ename, (*pt).ename);

    return 0;
}

Sample Output:

 Pointer : Show a pointer to union :                                                                          
----------------------------------------                                                                      
 Jhon Mc Jhon Mc 

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to declare a union and use a pointer to access and modify its members.
• Write a C program to demonstrate how a union works by assigning values to different members via a pointer.
• Write a C program to use a pointer to a union to display the same memory in different formats.
• Write a C program to show the effect of updating one union member on the values of other members using a pointer.

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