#include<stdio.h>
#define SIZE 100
int stack[SIZE];
int sp=0;

void push(int data){
printf("push> sp= %d\n",sp);
if(sp>=SIZE)return;
stack[sp]=data;
sp++;
}

int pop(void){
printf("pop> sp= %d\n",sp);
if(sp<=0)return-1;
sp--;
return stack[sp];
}

void printStack(void){
int i=0;
printf("printStack> ");
for(i=0;i<sp;i++)printf("%d ",stack[i]);
printf("\n");
}

int main(void){
push(1);
push(2);
push(3);
printStack();
printf("%d\n",pop());
printf("%d\n",pop());
printf("%d\n",pop());
printf("%d\n",pop());
return 0;
}