Understanding Scope and Block Structure

Snippet

Understanding Scope and Block Structure

Scope determines where variables can be accessed in your program. A variable defined inside a block (between curly braces) is only visible within that block. This concept is called block scope and helps organize code while preventing accidental variable misuse. Trying to access a variable outside its scope will cause a compilation error.

snippet.cpp
cpp
#include <iostream>
 
int main() {
    int x = 10;
    
    if (x > 5) {
        int y = 20;
        std::cout << "Inside block: " << x + y << std::endl;
    }
    
    std::cout << "Outside block: " << x << std::endl;
    
    return 0;
}

Breakdown

int x = 10;

Variable x is accessible everywhere inside main()

int y = 20;

Variable y only exists inside the if block

std::cout << x + y;

Works here because y is in scope inside the block

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Understanding Scope and Block Structure

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