#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

#define BUFSIZE 1000
#define MAXVALUE 1000
#define MAXOP 1000
#define NUMBER '0'

char bufor[BUFSIZE];
double heap[MAXVALUE];
int bufindex;
int heapindex;

int getch(void);
void ungetch(int c);
int getoperator(char s[]);
void push(double f);


int main()
{
    int op;
    double temp;
    char s[MAXOP];

    while((op == getoperator(s)) != EOF){
        switch(op) {
            case NUMBER:
                push(atof(op));
                break;
            case '*':
                push(pop()*pop());
                break;
        }
    }
}

void push(double f){
    if(heapindex < MAXVALUE)
        heap[heapindex++] = f;
    else
        printf("Koniec stosu!");
}

double pop(void){
    if (heapindex > 0)
        return heap[--heapindex];
    else {
        printf("Pusty stos!");
        return 0;
    }
}


int getoperator(char s[]){
    int i, c;
    while(c = getch() == ' ' || c == 't');

    s[1] = '';

    i = 0;

    if(!isdigit(c) && c != '.' && c != '-')
        return c;

    if(c=='-'){
        if(isdigit(c=getch()) || c == '.')
            s[++i] = c;
        else{
            if(c != EOF){
                ungetch(c);
            return '-';
            }
        }
    }

    if(isdigit(c))
        while(isdigit(s[++i] = c = getch()));
    if(c == '.')
        while(isdigit(s[++i] = c = getch()));

    s[i] = '';

    if (c != EOF)
        ungetch(c);
    return NUMBER;
}

int getch(void){
    return(bufindex > 0) ? bufor[--bufindex] : getchar();
}

void ungetch(int c){
    if(bufindex >= BUFSIZE)
        printf("Poza zakresem!");
    else
        bufor[bufindex++] = c;
}