(코드는 여기에)

(코드는 여기에)

(코드는 여기에)

(코드는 여기에)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct Node
{
	int data;
	struct Node* ptr;
}Node;

Node* stack = NULL;
Node* head = NULL;

void push(int input)
{
	Node* newNode;
	newNode = (Node*)malloc(sizeof(Node));
	newNode->data = input;
	newNode->ptr = head;
	head = newNode;
}

void pop()
{
	Node* topNode = head;
	if (head == NULL)
	{
		printf("-1\n");
	}
	else
	{
		int returnvalue = head->data;
		head = head->ptr;
		free(topNode);
		printf("%d\n", returnvalue);
	}
}

void print_stack()
{
	Node* temp = head;
	if (temp != NULL)
	{
		printf("Stack: ");
		do
		{
			printf("%d ", temp->data);
			temp = temp->ptr;
		} while (temp != NULL);
		printf("\n");
	}
	else
	{
		printf("The Stack is empty\n");
	}
}

void stack_size()
{
	Node* temp = head;
	int cnt = 0;
	while (temp != NULL)
	{
		cnt++;
		temp = temp->ptr;
	}
	printf("%d\n",cnt);
}

void stack_isempty()
{
	if (head == NULL)
	{
		printf("1\n");
	}
	else
	{
		printf("0\n");
	}
}

void stack_top()
{
	if (head != NULL)
	{
		printf("%d\n", head->data);
	}
	else
	{
		printf("-1\n");
	}
}

int main()
{
	int N, i, target;
	char str[12];
	char npush[] = "push";
	char ntop[] = "top";
	char nsize[] = "size";
	char nempty[] = "empty";
	char npop[] = "pop";
	scanf(" %d", &N);
	for (i = 0; i < N; i++)
	{
		scanf("%s", str);
		if (!strcmp(str,npush))
		{
			scanf(" %d", &target);
			push(target);
		}
		else if (!strcmp(str,ntop))
		{
			stack_top();
		}
		else if (!strcmp(str,nsize))
		{
			stack_size();
		}
		else if (!strcmp(str,npop))
		{
			pop();
		}
		else if (!strcmp(str,nempty))
		{
			stack_isempty();
		}
	}
	return 0;
}

(코드는 여기에)