c++ const shared_ptr

Explanation of using const with shared_ptr in C++

#include <iostream>
#include <memory>

int main() {
    const std::shared_ptr<int> p1 = std::make_shared<int>(42);
    // p1 = std::make_shared<int>(100); // Error: p1 is const, cannot be reassigned
    *p1 = 100; // OK: the value pointed to by p1 can be modified
    return 0;
}
  • Include Necessary Headers:

  • Include the necessary headers for using shared_ptr and other standard library components.

  • Create a Constant shared_ptr:

  • Declare a constant shared_ptr named p1 pointing to an integer with the value 42.

  • Error on Reassignment:

  • Attempting to reassign p1 to point to a different integer using std::make_shared<int>(100) results in a compilation error because p1 is constant.

  • Modifying Pointed Value:

  • Modifying the value pointed to by p1 using the dereference operator *p1 = 100 is allowed, as the constant shared_ptr only prevents reassignment of the pointer itself, not the value it points to.