Scope of variables in C++ - Mini Project: Build & Apply

Scope of variables in C++

📖 Scenario: Imagine you are organizing a small event and need to keep track of the number of guests in different rooms. You will learn how variable scope works in C++ by using variables inside and outside blocks.

🎯 Goal: You will create variables with different scopes and see how their values change inside and outside blocks.

📋 What You'll Learn

Create a global variable

Create a local variable inside a block

Use a nested block with a variable of the same name

Print variable values to see which one is used

💡 Why This Matters

🌍 Real World

Understanding variable scope helps avoid bugs when multiple parts of a program use the same names.

💼 Career

Knowing scope is essential for writing clear, maintainable code in any programming job.

1

Create a global variable

Create a global integer variable called guests and set it to 10.

C++

# Your code here

Need a hint?

Global variables are declared outside any function.

2

Create a local variable inside main

Inside the main function, create a local integer variable called guests and set it to 5.

C++

int guests = 10;

int main() {
    // Your code here
    return 0;
}

Need a hint?

Local variables are declared inside functions and hide global variables with the same name.

3

Create a nested block with a new variable

Inside the main function, add a nested block using curly braces { }. Inside this block, create another integer variable called guests and set it to 2.

C++

int guests = 10;

int main() {
    int guests = 5;
    {
        // Your code here
    }
    return 0;
}

Need a hint?

Variables declared in inner blocks hide variables with the same name in outer blocks.

4

Print variable values to see scope in action

Add std::cout statements to print the value of guests inside the nested block, inside main but outside the nested block, and outside main (use the global variable). Use std::cout and std::endl to print each value on its own line.

C++

int guests = 10;

int main() {
    int guests = 5;
    {
        int guests = 2;
        // Your code here
    }
    // Your code here
    return 0;
}
// Your code here

Need a hint?

Use ::guests to access the global variable inside main.