Dereferencing a null pointer in C++ leads to undefined behavior. A null pointer is a pointer that does not point to any valid memory address. When you attempt to dereference a null pointer, you are trying to access the value stored at the memory location it points to, but since it doesn't point to anything valid, the behavior is undefined.
Undefined behavior means that the result of such an operation is not predictable or specified by the language. It can lead to program crashes, unexpected results, or even security vulnerabilities. The behavior may vary depending on the compiler, platform, and other factors, making it unreliable and potentially dangerous.
To avoid dereferencing null pointers, it is crucial to ensure that a pointer is valid and not null before attempting to access the memory it points to. You can perform a null check using an if statement or other appropriate means before dereferencing the pointer. This practice helps prevent undefined behavior and allows for safer and more reliable code execution.
