CodeGym/Help with Java Tasks/colors not displayed

Level 7

Enschede

26.12.2018
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colors not displayed

Question about the task

Crossing the road blindly

Java Syntax, Level 4, Lesson 4

Resolved

At my compiler it is working, but when I click to verify it keeps telling me that the colors are not displayed..

The pedestrian traffic light is programmed as follows:
at the beginning of each hour, the green signal is on for three minutes,
then the signal is yellow for one minute,
and then it is red for one minute.
Then the light is green again for three minutes, etc.
Use the keyboard to enter a real number t that represents the number of minutes that have elapsed since the beginning of the hour.
Determine what color the traffic light is at the specified time.
Display the result as follows:
"green" if the light is green,
"yellow" if the light is yellow, and
"red" if the light is red.

Example for 2.5:
green
Example for 3:
yellow
Example for 4:
red
Example for 5:
green

Requirements:

The program should read a real number from the keyboard.
The program should display text on the screen.
If the light is green, display: "green"
If the light is yellow, display: "yellow"
If the light is red, display: "red"

package com.codegym.task.task04.task0416; /* Crossing the road blindly */ import java.io.*; public class Solution { public static void main(String[] args) throws Exception { InputStreamReader ISR = new InputStreamReader(System.in) ; BufferedReader BR = new BufferedReader(ISR); String someString = BR.readLine(); double traffic = Double.parseDouble(someString); if((traffic <= 3) || ((traffic <= 8) && (traffic > 5)) || ((traffic <= 13) && (traffic > 10)) || ((traffic <= 18) &&(traffic > 15)) || ((traffic <= 23) && (traffic > 20)) || ((traffic <= 28) && (traffic > 25)) || ((traffic <= 33) && (traffic > 30)) || ((traffic <= 38) && (traffic > 35)) || ((traffic <= 43) && (traffic > 40)) || ((traffic <= 48) && (traffic > 45)) || ((traffic <= 53) && (traffic > 50)) || ((traffic <= 58) && (traffic > 55))) System.out.println("green"); else if (((traffic <= 4) && (traffic > 3)) || ((traffic <= 9) && (traffic > 8)) || ((traffic <= 14) && (traffic > 13)) || ((traffic <= 19) && (traffic > 18)) || ((traffic <= 24) && (traffic > 23)) || ((traffic <= 29) && (traffic > 28)) || ((traffic <= 34) && (traffic > 33)) || ((traffic <= 39) && (traffic > 38)) || ((traffic <= 44) && (traffic > 43)) || ((traffic <= 49) && (traffic > 48)) || ((traffic <= 54) && (traffic > 53)) || ((traffic <= 59) && (traffic > 58)) ) System.out.println("yellow"); else System.out.println("red"); } }

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Vadym

Level 16

31 December 2018, 15:42

Tell me please, why you use this formula?

traffic=traffic%5;

Level 8 , Wietzendorf, Germany

20 January 2019, 14:56

The green - yellow - red block is 5 minutes long. 3 minutes green, 1 minute yellow, 1 minute red. If you use modulo you can make it a lot easier because you can just see if the result of t % 5 is <3 or <4.

Sabine Meijran-Prins

Level 7 , Enschede, Netherlands

26 December 2018, 13:31

I have changed the extremely long if-statements into modulo statements. but I still have the same problem. Although it works in my compiler, this program is telling me that it isn't working import java.io.*;

public class Solution {
    public static void main(String[] args) throws Exception {

    InputStreamReader ISR = new InputStreamReader(System.in)   ;
    BufferedReader BR = new BufferedReader(ISR);

    String someString = BR.readLine();
    double traffic = Double.parseDouble(someString);

    traffic=traffic%5;

    if(traffic <=3)

    System.out.println("green");



    else if ((traffic <= 4) && (traffic > 3))
    System.out.println("yellow");
    else
    System.out.println("red");



    }
}

Guadalupe Gagnon

Level 37 , Tampa, United States

26 December 2018, 14:43

If you look at the examples, if after modulo the result is less than 3 it is green, then less than 4 it should be yellow, and the rest should be red. If you enter 3 in to yours it returns green, and 4 returns yellow. My first sentence is a big clue on how to solve. Good luck!

Sabine Meijran-Prins

Level 7 , Enschede, Netherlands

26 December 2018, 15:15

Thank you for the hint, I will working on it :)

dean

Level 8 , Deutschland, Germany

21 April 2019, 08:48

thanks was very helpful your comment, but you knew to use modulo 5? is there a formula to figure what modulo one should use for each challenge? thanks!

Guadalupe Gagnon

Level 37 , Tampa, United States

22 April 2019, 13:01

@Dean They tell you. This one specifically says 3 minutes, 1 minute, and 1 minute. That equals 5. Have to pay attention to the details of the task.

dean

Level 8 , Deutschland, Germany

22 April 2019, 13:40

yes i know that but because they said 5 mins doesn't mean the remaining needed to be 5 as well... that's why i asked if there's a formula for it...

Guadalupe Gagnon

Level 37 , Tampa, United States

22 April 2019, 14:21

That is the task, every 5 minutes the light will be green for 3, yellow for 1, and red for 1. So if you mod by 5 the remainder will tell you what color it will be: anything less than 2.99 will be green, less than 3.99 will be yellow, and the remaining will be red.

dean

Level 8 , Deutschland, Germany

22 April 2019, 15:52

oright thanks!