stack.cpp

#include <bits/stdc++.h>

using namespace std;

#define new_node (link*)malloc(sizeof(link));

class MyStack {
	private:
		struct link {
			int val; 
			link *next;
		};
		link *first = NULL , *last = NULL;
		int size = 0;
		public:
void Push (int v) {
	size++;
	link *pp = new_node;
	pp->val = v;
	pp->next = NULL;
	if (first == NULL) {
		first = pp;
		last = pp;
	}
	else {
		pp->next = first;
		first = pp;
	}
}
int Top () {
	link *x = first;
	return x->val;
}

void Pop () {
	if (size > 0) size--;
	link *x = first->next;
	first = x;
}

void Print () {
	link *x = first;
	while (x != NULL) {
		cout << x->val << endl;
		x = x->next;
	}
//	cout << x->val << endl;
}

bool Search (int v) {
	link *x = first;
	while (x != NULL) {
		if (x->val == v) {
			return 1;
		}
		x = x->next;
	}
	return 0;
}

void Remove (int v) {
	link *x = first; 
	link *y = first->next;
	
	while (y != NULL) {
		if (y->val == v){
			size--;
			x->next = y->next;
		}
		x = x->next;
		y = y->next;
	}
}

int Size () {
	return size;
}

};

int main () {
    MyStack ST;
	int n; cin >> n; 
	for (int i = 0; i < n; i++) {
		int x; 
		cin >> x; 
		ST.Push(x);
	} 	
	while (1) {
		string ss;
		cin >> ss;
		if (ss == "push") {
			int x;
			cin >> x;
			ST.Push(x);
		}
		else if (ss == "pop") {
			ST.Pop();
		}
		else if (ss == "remove") {
			int x; 
			cin >> x;
			ST.Remove(x);
		}
		else if (ss == "print"){
			ST.Print();
		}
		else if (ss == "size" ) {
			cout << ST.Size() << endl;
		}
	}
}