What are the differences between a reference and a pointer in programming?

A pointer and a reference are different ways of working with memory addresses:

• Pointer — a variable that stores the address of another variable. Pointers can be changed, reassigned, and can point to nullptr or different objects. In C++, operators * (dereference) and & (address-of) are used to work with pointers.

• Reference — an alternative name for an existing variable. Once initialized, a reference cannot be reassigned to another object and cannot be nullptr. References provide a safer and more convenient syntax for working with objects.

Example:

int a = 10;
int b = 20;

int* ptr = &a; // pointer to a
ptr = &b;      // now points to b

int& ref = a;  // reference to a
// ref = b;    // this is not reassigning the reference, but assigning the value of b to a

Thus, pointers are more flexible but require caution, while references are simpler and safer to use.