What is the purpose of a double pointer in the C language?

In C language, a double pointer refers to a pointer that points to another pointer, which means a pointer to a pointer. Its purpose is to allow modifying the address pointed to by a pointer in a function or modifying the value pointed to by a pointer in a function. By using double pointers, more flexible memory management and data manipulation can be achieved, enhancing the scalability and functionality of a program. Common applications include dynamic memory allocation, linked list operations, and multi-dimensional arrays.