pointer to constant

#include <iostream>

int main() {
    int variable = 42;
    const int* ptr = &variable;

    std::cout << "Value of variable: " << variable << std::endl;
    std::cout << "Value pointed to by ptr: " << *ptr << std::endl;

    // Compilation error: Cannot modify a const-qualified variable
    // *ptr = 20;

    variable = 20;

    std::cout << "Updated value of variable: " << variable << std::endl;
    std::cout << "Updated value pointed to by ptr: " << *ptr << std::endl;

    return 0;
}