Accessing structure members in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of accessing structure members with dot operator

What is the output of this C++ code snippet?

C++

struct Point {
    int x;
    int y;
};

int main() {
    Point p = {3, 4};
    std::cout << p.x << "," << p.y << std::endl;
    return 0;
}

A Compilation error

B 3,4

C 4,3

D x=3,y=4

💡 Hint

Remember the dot operator accesses members directly by name.

The structure Point has members x and y. The code initializes p.x=3 and p.y=4, so printing p.x and p.y outputs '3,4'.

❓ Predict Output

intermediate

Output when accessing structure members via pointer

What will this C++ program print?

C++

struct Data {
    int value;
};

int main() {
    Data d = {10};
    Data* ptr = &d;
    std::cout << ptr->value << std::endl;
    return 0;
}

A Garbage value

B Compilation error

C 10

D 0

💡 Hint

Use the arrow operator to access members through pointers.

The pointer ptr points to d, which has value 10. Using ptr->value accesses that member correctly.

❓ Predict Output

advanced

Output of nested structure member access

What is the output of this code?

C++

struct Inner {
    int a;
};

struct Outer {
    Inner inner;
};

int main() {
    Outer o = {{5}};
    std::cout << o.inner.a << std::endl;
    return 0;
}

A 5

B Compilation error

C 0

D Garbage value

💡 Hint

Access nested members by chaining dot operators.

The Outer structure contains Inner named inner. The value a is initialized to 5 and printed.

❓ Predict Output

advanced

Output when accessing structure members with pointer and dot

What happens when you run this code?

C++

struct Item {
    int id;
};

int main() {
    Item item = {7};
    Item* p = &item;
    std::cout << (*p).id << std::endl;
    return 0;
}

A 7

B Compilation error

C 0

D Runtime error

💡 Hint

Dereference pointer first, then use dot operator.

(*p).id accesses the id member of the object pointed to by p, which is 7.

🧠 Conceptual

expert

Error type when accessing structure member incorrectly

What error will this code produce?

C++

struct Sample {
    int x;
};

int main() {
    Sample* s = nullptr;
    std::cout << s->x << std::endl;
    return 0;
}

A Compilation error

B Undefined behavior but no crash

C Output: 0

D Segmentation fault (runtime error)

💡 Hint

Accessing member through null pointer causes crash.

Dereferencing a null pointer to access a member causes a segmentation fault at runtime.