Please help me! I don't understand what to do at all...

Question about the task

Under discussion

Just give me a hint how to resolve it...I saw that a lot of people was saying to use modulus..but i don't understand how to use it in this task... Thanks in advance:)

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 { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String T = reader.readLine(); double t = Double.parseDouble(T); if (t > 0 && t < 3){ System.out.println("green"); } else if (t >= 3 && t < 4 ){ System.out.println("yellow"); } else if (t >= 4 && t < 5){ System.out.println("red"); } } }

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J H U X

Level 7 , Alkmaar, Netherlands

17 January 2021, 16:27

You're SO close. Write double t = Double.parseDouble(T) % 5; <-- this gives you the 'rest'. Now you have to check if the 'rest' is equal to, or greater than zero, but smaller than 3 (for green). So first if statement should say t >= 0 && t < 3. Rest of your code is great, so I think you get the idea just fine. Good luck!

Albert

Level 6 , Hong Kong, Hong Kong

20 November 2020, 03:52

Since every hour has 12 sections of 5 minutes, a while loop might help simplify the case by: while (t<=60 && t>=5){ t = t-5; }

ashleybee19

Level 8 , Seattle, United States

6 October 2020, 17:23

You're right, using modulus is the key here. Every 5 minutes the lights will loop through green, yellow, and red. For the first 3 minutes the light will be green, so when t >= 0 && when t < 3. But after 5 minutes this will happen again, so from t >= 5 && t < 8, the light will also be green. We could keep repeating this for the full hour for each color, or we could use modulus. Every green light will start with a number divisible by 5, and end with a number that, when divided by 5, has a remainder of 3. Does this help?

Ahmad Dabagh

Level 9 , Hannover, Germany

15 October 2020, 08:04

Thanks

Nouser

Level 36 , Germany

4 October 2020, 13:48

try:

double t = Double.parseDouble(T) % 5;

eg. 12.8 or 7.8 % 5 would give 2.8