C language questions:

here is the basic helper function about stack:

thanks!!!

#include #include #include "stack" h" /f creates a new stack stack t* stack create) stack-t* s = (stack-t*) s->top = NULL return s; nal loc(sizeof (stack-t)): // pushes a given item to the stack Pre condition: stack is not empty void stack push (stack t* s, void* item) node t* newTop- (node t*) malloc (sizeof (node t)); newTop->data - item s-topnewTop / pops the top element from the stack // Pre condition: stack is not empty void* stack pop (stack t* s) void* ret -s->top->data node t* prevlop s-top s-topprevTop-next freelprevTop) return ret; // retums 1 if the stack is empty int stack_is_empty(stackt* s) tack is empty, and returns 0 otherwise return (s->top - NULL) void stack free (stack t* s) while (s-top) node-t prevTop = s->top s->top = prevTop->next freelprevTop) free(s #include #include #include "stack" h" /f creates a new stack stack t* stack create) stack-t* s = (stack-t*) s->top = NULL return s; nal loc(sizeof (stack-t)): // pushes a given item to the stack Pre condition: stack is not empty void stack push (stack t* s, void* item) node t* newTop- (node t*) malloc (sizeof (node t)); newTop->data - item s-topnewTop / pops the top element from the stack // Pre condition: stack is not empty void* stack pop (stack t* s) void* ret -s->top->data node t* prevlop s-top s-topprevTop-next freelprevTop) return ret; // retums 1 if the stack is empty int stack_is_empty(stackt* s) tack is empty, and returns 0 otherwise return (s->top - NULL) void stack free (stack t* s) while (s-top) node-t prevTop = s->top s->top = prevTop->next freelprevTop) free(s