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

#define STACK_SIZE 10


struct stack {
   float values[STACK_SIZE];
   int size;
};


void init(struct stack *s){
    s->size=0; //inicializacia stacku
}

int is_empty(struct stack *s){return s->size==0;} // check if stack is empty
int is_full(struct stack *s){return s->size==STACK_SIZE;}


void push(struct stack *s, float value){
    if (is_full(s)){
        printf("full stack\n");
        exit(0);
    }
    s->values[s->size++]=value; // pridava cislo do stacku a size +=1
}

float pop (struct stack *s){
    if (is_empty(s)){
        printf("Stack is empty");
        return 1;
    }
    return s->values[--(s->size)]; // najprv - size, potom vybera jednu polozku
}


void print_s(struct stack *s){
    for(int i =0;i<s->size;i++){
        printf("%.2f ", s->values[i]);
    }
    printf("\n");
}


int main(){
    struct stack mystack;
    init(&mystack);

    char input[100];

    while(fgets(input, sizeof(input), stdin)){
        input[strcspn(input,"\n")]='\0';

        char *endpt;
        float num = strtod(input,&endpt); // oddeli vsetky cisla (medzerami) a posledne zapise do endpt

        if(endpt!=input&&*endpt=='\0'){ // ked endpt!= plnomu inputu a nie je koncom inputu
            push(&mystack,num);
        }
        else if (strlen(input)==1&&strchr("+-*/",input[0])){ // ak dlzka inputu po upravach 1 a to nojeaky operator  
            if (mystack.size<2){ // previerka na to ci mame cisla pre operacie
                printf("not enough operands\n");
                return 0;}
            float b=pop(&mystack);
            float a = pop(&mystack);
            float result = 0;

            if (input[0]=='+') result=a+b;
            if (input[0]=='-') result=a-b;
            if (input[0]=='*') result=a*b;
            if (input[0]=='/'){
                if (b==0) {printf("division by zero\n");return 0;}
                result=a/b;
            }
            push(&mystack, result);
        }
        else{
            printf("bad input\n");
            return 0;
        }
        print_s(&mystack);
    }
    
    printf("no input\n");
    return 0;
}