A constant pointer is a pointer in C or C++ that points to a constant value, and its value cannot be changed. It is declared using the “const” keyword before the pointer variable name.
For example, consider the following code:
int x = 5;
const int *ptr = &x;
Here, the pointer variable ptr is a constant pointer, which means it points to an integer constant (in this case, the value of x). Since the pointer is constant, we cannot change the value it points to using the pointer. In other words, the following code would result in a compiler error:
*ptr = 10; // error: assignment of read-only location '*ptr'
However, we can still change the value of x itself, as it is not declared as a constant:
x = 10; // OK
It is important to note that a constant pointer does not necessarily mean that the value being pointed to is constant, but rather that the pointer itself is constant and cannot be used to modify the value it points to.
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