typedef struct Node *PtrToNode

As an AI language model, I can provide you with an explanation of what typedef, struct, and pointer are:

- typedef is a keyword in C programming that allows you to create an alias or a new name for an existing data type. This can make your code more readable and easier to maintain.

- struct is a keyword in C programming that allows you to define a new data type that consists of multiple related variables or fields. This can be useful for organizing data in a structured way.

- pointer is a variable that stores the memory address of another variable. Pointers can be used to access and manipulate data indirectly, which can be useful for dynamic memory allocation and passing data between functions.

Now, with that context in mind, the code snippet you provided is declaring a new data type called PtrToNode, which is a pointer to a struct Node. This means that PtrToNode will store the memory address of a Node struct, allowing you to access the fields of the struct indirectly through the pointer.