#include "stdafx.h"
#include "conio.h"

   #DEFINE MAXOP   '20'  
   #DEFINE NUMBER '0'  
   #DEFINE TOOBIG '9' 

   INT TUPE;
    CHAR S[MAXOP];
    DOUBLE OP2,ATOF(),POP(),PUSH();

    WHILE ((TUPE=GETOP(S,MAXOP)) !=EOF);
      SWITCH(TUPE) /(
      CASE NUMBER:
           PUSH(ATOF(S));
           BREAK;
      CASE '+':
           PUSH(POP()+POP());
           BREAK;
      CASE '*':
           PUSH(POP()*POP());
           BREAK;
      CASE '-':
           OP2=POP();
           PUSH(POP()-OP2);
           BREAK;
      CASE '/':
           OP2=POP();
           IF (OP2 != 0.0)
   PUSH(POP()/OP2);
           ELSE
              PRINTF("ZERO DIVISOR POPPED\N");
           BREAK;
      CASE '=':
           PRINTF("\T%F\N",PUSH(POP()));
           BREAK;
      CASE 'C':
           CLEAR();
           BREAK;
      CASE TOOBIG:
           PRINTF("%.20S ... IS TOO LONG\N",S)
           BREAK;
   
   #DEFINE MAXVAL 100 /* MAXIMUM DEPTH OF VAL STACK */

   INT SP = 0;        /* STACK POINTER */
   DOUBLE VAL[MAXVAL]; /*VALUE STACK */
   DOUBLE PUSH(F)    /* PUSH F ONTO VALUE STACK */
   DOUBLE F;

    IF (SP < MAXVAL)
            RETURN(VAL[SP++] =F);
    ELSE    /(
            PRINTF("ERROR: STACK FULL\N");
            CLEAR();
            RETURN(0);
   
   DOUBLE POP()   /* POP TOP VALUE FROM STEACK */

    IF (SP > 0)
            RETURN(VAL[--SP]);
    ELSE    /(
            PRINTF("ERROR: STACK EMPTY\N");
            CLEAR();
            RETURN(0);
  

   CLEAR()       /* CLEAR STACK */
  
     SP=0;
 
     
 getch();
return 0;
}