Nested structures in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested struct member access

What is the output of this C++ code?

C++

struct Point {
    int x;
    int y;
};

struct Rectangle {
    Point topLeft;
    Point bottomRight;
};

#include <iostream>
int main() {
    Rectangle rect = {{1, 4}, {5, 1}};
    std::cout << rect.topLeft.x << "," << rect.bottomRight.y << std::endl;
    return 0;
}

A 1,4

B 5,4

C 5,1

D 1,1

💡 Hint

Look at how the nested points are initialized and which members are accessed.

The Rectangle struct has two Points: topLeft and bottomRight. topLeft.x is 1, bottomRight.y is 1, so output is '1,1'.

❓ Predict Output

intermediate

Output of nested struct with array member

What will this program print?

C++

struct Team {
    struct Player {
        int id;
        int score;
    } players[3];
};

#include <iostream>
int main() {
    Team team = {{{1, 10}, {2, 20}, {3, 30}}};
    std::cout << team.players[1].score << std::endl;
    return 0;
}

A 10

B 20

C 30

D 1

💡 Hint

Check which player index is accessed and which member is printed.

players[1] is the second player with id=2 and score=20, so output is 20.

🔧 Debug

advanced

Identify the error in nested struct initialization

This code tries to initialize nested structs but causes a compilation error. What is the error?

C++

struct Date {
    int day;
    int month;
    int year;
};

struct Event {
    char name[20];
    Date date;
};

int main() {
    Event e = {"Meeting", {12, 5}};
    return 0;
}

A Struct Event cannot contain another struct

B Cannot initialize char array with string literal

C Missing year value in nested Date initialization

D Missing semicolon after struct definitions

💡 Hint

Check how many values are needed to initialize Date.

Date requires three integers (day, month, year), but only two are provided, causing a compilation error.

📝 Syntax

advanced

Correct syntax to access nested struct member

Which option correctly accesses the 'z' member inside nested structs?

C++

struct Inner {
    int z;
};

struct Outer {
    Inner inner;
};

Outer o = {{5}};

A o.inner.z

B o->inner.z

C o.inner->z

D o->inner->z

💡 Hint

Remember the difference between dot (.) and arrow (->) operators.

o is an object, so use dot operator to access members. Arrow operator is for pointers.

🚀 Application

expert

Calculate total price from nested structs

Given the structs below, what is the total price printed by the program?

C++

struct Item {
    char name[10];
    int quantity;
    double price_per_unit;
};

struct Order {
    Item items[2];
};

#include <iostream>
int main() {
    Order order = {{{"Pen", 10, 1.5}, {"Notebook", 5, 3.0}}};
    double total = 0;
    for (int i = 0; i < 2; ++i) {
        total += order.items[i].quantity * order.items[i].price_per_unit;
    }
    std::cout << total << std::endl;
    return 0;
}

A 30

B 25

C 20

D 35

💡 Hint

Multiply quantity by price for each item and add them up.

Pen: 10 * 1.5 = 15, Notebook: 5 * 3.0 = 15, total = 30.0