#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>

#define STACK_SIZE 20

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

void print_stack(struct stack* stack);
void push_stack(struct stack* stack, float value);
float pop_stack(struct stack* stack);
int count_stack(struct stack* stack);



int main(){
    

    char char_value[STACK_SIZE];
    memset(&char_value,0,STACK_SIZE);
    float float_value;
    char* ptr;
    struct stack myStack;
    memset(&myStack,0,sizeof(struct stack));
    while(1){
        ptr = fgets(char_value, STACK_SIZE-1, stdin);
        if(ptr != NULL ){
            if(char_value[0] == '0'){
                push_stack(&myStack,0);
                print_stack(&myStack);
                printf("\n");
                continue;
            }
            float_value = strtof(char_value, NULL);
            if(float_value == 0){
                if(char_value[0] == '+'){
                    float a = pop_stack(&myStack);
                    float b = pop_stack(&myStack);                    
                    float c = a+b;
                    push_stack(&myStack, c);
                    print_stack(&myStack);
                    printf("\n");
                }
                if(char_value[0] == '-'){
                    float a = pop_stack(&myStack);
                    float b = pop_stack(&myStack);                    
                    float c = b-a;
                    push_stack(&myStack, c);
                    print_stack(&myStack);
                    printf("\n");
                }
                if(char_value[0] == '*'){
                    float a = pop_stack(&myStack);
                    float b = pop_stack(&myStack);                    
                    float c = a*b;
                    push_stack(&myStack, c);
                    print_stack(&myStack);
                    printf("\n");
                } 
                if(char_value[0] == '/'){
                    float a = pop_stack(&myStack);
                    if(a == 0){
                        printf("division by zero\n");
                        break;
                    }
                    float b = pop_stack(&myStack);                    
                    float c = b/a;
                    push_stack(&myStack, c);
                    print_stack(&myStack);
                    printf("\n");
                }
 
            }else { 
                
                push_stack(&myStack, float_value);
                print_stack(&myStack);
                printf("\n");
            }
        }else{
            puts("no input");
            break;
        }
    } 


    return 0;
}

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

void push_stack(struct stack* stack, float value){
    assert(stack->size < STACK_SIZE);
    stack->values[stack->size] = value;
    stack->size += 1;
}

float pop_stack(struct stack* stack){
    assert(stack->size > 0);
    float value = stack->values[stack->size-1];
    stack->size -= 1;
    return value;
}