A classical stack operation using a string of characters.
#include <iostream>
#include <string.h>
using namespace std;
#define maxlen 80

class stack {
 char str1[maxlen];
 int  first;   
public:
 void clear(void);
 char top(void);
 int  empty(void);
 int  full(void);
 void push(char chr);
 char pop(void);
};

void stack::clear(void)
{
 first=0;
}   
  char stack::top(void)
{
 return (str1[first]);
}

int stack::empty(void)
{
 return (first==0);
}

int stack::full(void)
{
 return (first==maxlen-1);
}

void stack::push(char chr)
{
 str1[++first]=chr;
}   
char stack::pop(void)
{
 return (str1[first-1]);
}

main( )
{
 stack mystack;
 char str[11]="0123456789";

 mystack.clear( );
  
 for(int i=0; (int) i<strlen(str);i++) {
   if (!mystack.full( ))
     mystack.push(str[i]);
     cout << str[i] << endl;
 }
 while (!mystack.empty( ))
   cout << mystack.pop( ) << endl;
 
 return (0);
}