#include <iostream>
using namespace std;
int test,rozmiar;
short* tablica=new short [test];
short* glowa=tablica;
void push(short* liczba)
{
*tablica=*liczba;
tablica++;
}
void pop()
{
cout<<*glowa<<"\n";
glowa++;
}
void size()
{
rozmiar=tablica-glowa;
cout<<rozmiar<<"\n";
}
int main()
{
cin>>test;
for(int i=0;i<test;i++)
{
char znak;
short liczba;
cin>>znak;
switch(znak)
{
case '+':
cin>>liczba;
push(&liczba);
break;
case '-':
pop();
break;
case '?':
size();
break;
}
}
delete [] tablica;
return 0;
}
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