Using C Language: For the following problem define a stackNode struct with data of type double. Implement the following operations for your stack data structure:

1. isEmpty() a predicate function which checks to see if the stack is empty; returns true if the stack is empty

2. push() inserts a node to the top of the stack; the node is allocated dynamically

3. pop() deletes a node from the top of the stack

4. top() or peek() returns the data in the node at the top of the stack