스택형으로 문자를 출력하려고 하는데.; 숫자가 나와여;;;어떻게 해야 되나요

#include <iostream.h>

#define SIZE 100

class stack{
int stck[SIZE];
int tos;
public:
void init();
void push(char i);
int pop();
};

void stack::init()
{tos = 0; }

void stack::push(char i)
{
if(tos==SIZE) {
return;}
stck[tos] = i;
tos++;}

int stack::pop(){
if(tos==0) {
return 0;}
tos--;
return stck[tos];}
main(){
stack stack1, stack2;
stack1.init();
stack2.init();

stack1.push('v');
stack2.push('a');

cout << stack1.pop() << "";
cout << stack2.pop() << "";
return 0;
}