C++ basics -const decorates a pointer

Const modifies a pointer in three cases:

1. Const decorates Pointers — constant Pointers

const int * p = &a;

The point of a pointer can be changed, but the value it points to cannot be changed.

Memory tip: Const followed by *p indicates that the value to which the pointer points cannot be modified.

2. Const decorates constants — pointer constants

int * const p = &a;

The point of a pointer cannot be changed, but the value it points to can be changed.

Memory tip: Const followed by p, indicating that the pointer cannot be changed, p for address.

3. Const modifies both Pointers and constants

const int * const p = &a;

Neither the pointer nor the pointer value can be modified.

int main(a)
{
    int a = 10;
    int b = 10;
    
    // Contst modifies the pointer. The pointer pointer can be changed, but the pointer value cannot be changed
    const int * p1 = &a;
    p1 = &b; / / right
    //*p1 = 100; An error
    
    
    // Const modifies constants. The pointer to a pointer cannot be changed. The value to which a pointer points can be changed
    int * const p2 = &a;
    //p2 = &b; error
    *p2 = 100; / / right
    
    
    //const decorates both Pointers and constants
    const int * const p3 = &a;
    //p3 = &b; error
    //*p3 = 100; error
    
    return 0;
}
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