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

#define STACK_SIZE 10
struct stack_glavny {
    float data[STACK_SIZE];
    int size;
};


void initialize(struct stack_glavny* stack) {
    stack->size = -1;
}


int push(struct stack_glavny* stack, float value) {
    if (stack->size < STACK_SIZE - 1) {
        stack->size++;
        stack->data[stack->size] = value;
        return true;
    } else {
        return false;
    }
}


int pop(struct stack_glavny* stack, float* result) {
    if (stack->size >= 0) {
        *result = stack->data[stack->size];
        stack->size--;
        return true;
    } else {
        return false;
    }
}


int operation_insert_result(struct stack_glavny* stack, char operation) {
    float operand1, operand2, result;
    if (pop(stack, &operand2) && pop(stack, &operand1)) {
        switch (operation) {
            case '+':
                result = operand1 + operand2;
                break;
            case '-':
                result = operand1 - operand2;
                break;
            case '*':
                result = operand1 * operand2;
                break;
            case '/':
                if (operand2 == 0) {
                    printf("division by zero\n");
                    return false;
                }
                result = operand1 / operand2;
                break;
            default:
                //printf("Chyba: Neplatná operácia.\n");
                return false;
        }
        if (!push(stack, result)) {
            //printf("Chyba: Zásobník je plný.\n");
            return false;
        }
        return true;
    } else {
        printf("not enough operands\n");
        return false;
    }
}

int main() {
    struct stack_glavny stack;
    initialize(&stack);

    char input[20];
    
    while (1) {
        char* a = fgets(input, sizeof(input), stdin);
        if (a == NULL){
            printf("no input\n");
            break;
        }
    
    float value;
        
        //strchr aj strrchr hľadá prvý výskyt znaku určeného znakom v reťazci, na ktorý reťazec ukazuje.
        if (sscanf(input, "%f", &value) == 1 && strchr(input, '.') == strrchr(input, '.')) {
            if (!push(&stack, value)) {
                printf("bad input\n");
                break;
            }
        } else if (input[0] == '+' || input[0] == '-' || input[0] == '*' || input[0] == '/') {
            if (!operation_insert_result(&stack, input[0])) {
                break;
            }
        } else {
            printf("bad input\n");
            break;
        }
        for (int i = 0; i <= stack.size; i++) {
            printf("%.2f ", stack.data[i]);
        }
        printf("\n");
    }
    return 0;
}