1 20 points Suppose that you have a stack astack and an emp

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1. (20 points) Suppose that you have a stack astack and an empty auxiliary stack auxStack. Show how you can do each of the following tasks by using only the ADT stack operations. Write code fragments, not functions. Make no assumptions about the stack implementation (it could be any). Use only stack methods: (Download below) a. Display the contents of astack in reverse order; that is, display the top last. b. Count the number of items in astack, leaving astack unchanged. c. Delete every occurrence of a specified item from astack, leaving the order of the remaining items unchanged

Solution

A)

#include<stdio.h>
#include<stdlib.h>
#define bool int
struct sNode
{
char data;
struct sNode *next;
};
void push(struct sNode** top_ref, int new_data);
int pop(struct sNode** top_ref);
bool isEmpty(struct sNode* top);
void print(struct sNode* top);
void insertAtBottom(struct sNode** top_ref, int item)
{
if (isEmpty(*top_ref))
push(top_ref, item);
else
{
int temp = pop(top_ref);
insertAtBottom(top_ref, item);
push(top_ref, temp);
}
}
insertAtBottom()
void reverse(struct sNode** top_ref)
{
if (!isEmpty(*top_ref))
{
int temp = pop(top_ref);
reverse(top_ref);
insertAtBottom(top_ref, temp);
}
}
int main()
{
struct sNode *s = NULL;
push(&s, 4);
push(&s, 3);
push(&s, 2);
push(&s, 1);
printf(\"\ Original Stack \");
print(s);
reverse(&s);
printf(\"\ Reversed Stack \");
print(s);
return 0;
}
bool isEmpty(struct sNode* top)
{
return (top == NULL)? 1 : 0;
}
void push(struct sNode** top_ref, int new_data)
{
struct sNode* new_node =
(struct sNode*) malloc(sizeof(struct sNode));

if (new_node == NULL)
{
printf(\"Stack overflow \ \");
exit(0);
}
new_node->data = new_data;
new_node->next = (*top_ref);
(*top_ref) = new_node;
}
int pop(struct sNode** top_ref)
{
char res;
struct sNode *top;
if (*top_ref == NULL)
{
printf(\"Stack overflow \ \");
exit(0);
}
else
{
top = *top_ref;
res = top->data;
*top_ref = top->next;
free(top);
return res;
}
}
void print(struct sNode* top)
{
printf(\"\ \");
while (top != NULL)
{
printf(\" %d \", top->data);
top = top->next;
}
}