Structures and Unions Interview Questions

    Question 1: Structure Basics

    What is a structure in C?

    Question 2: Structure Declaration

    Which is the correct way to declare a structure?

    Question 3: Structure Access

    What will be the output?

    #include <stdio.h>

struct Point {
    int x, y;
};

int main() {
    struct Point p = {10, 20};
    printf("%d %d", p.x, p.y);
    return 0;
}

    Question 4: Pointer to Structure

    What will be printed?

    #include <stdio.h>

struct Student {
    int id;
};

int main() {
    struct Student s = {101};
    struct Student *p = &s;
    printf("%d", p->id);
    return 0;
}

    Question 5: Difference between Structure and Union

    What is the key difference between structure and union in C?

    Question 6: Size of Structure

    What will sizeof return?

    #include <stdio.h>

struct Test {
    int a;
    char b;
};

int main() {
    printf("%zu", sizeof(struct Test));
    return 0;
}

    Question 7: Union Behavior

    What will be printed?

    #include <stdio.h>

union Data {
    int i;
    char c;
};

int main() {
    union Data d;
    d.i = 65;
    printf("%c", d.c);
    return 0;
}

    Question 8: Nested Structures

    Which of the following is valid for nested structures?

    Question 9: Structure vs Array

    Which statement is true?

    Question 10: Union Size

    What will sizeof return?

    #include <stdio.h>

union U {
    int a;
    double b;
    char c;
};

int main() {
    printf("%zu", sizeof(union U));
    return 0;
}