Challenge: Traffic Light

Lab C++ Beginner 10 points

Use enum class Light { Red, Yellow, Green };. Read a word (red, yellow or green), turn it into a Light, and print what the next light will be and what to do. The order is Green → Yellow → Red → Green.

Input

One word.

Output

For green: Next: yellow (slow down). For yellow: Next: red (stop). For red: Next: green (go).

Example

Input

green

Output

Next: yellow (slow down)

Sample input available Sample output available

Editor

C++

Hints

Turn the word into a Light with if statements.

Write a function Light next(Light l) using switch.

Solution explanation

Once the text is turned into an enum class value, the rest of the program works with clear, safe names.

Show solution

#include <iostream>
#include <string>
using namespace std;

enum class Light { Red, Yellow, Green };

Light next(Light l) {
    switch (l) {
        case Light::Green:  return Light::Yellow;
        case Light::Yellow: return Light::Red;
        case Light::Red:    return Light::Green;
    }
    return Light::Red;
}

int main() {
    string word;
    cin >> word;
    Light now = Light::Red;
    if (word == "yellow") now = Light::Yellow;
    if (word == "green") now = Light::Green;

    switch (next(now)) {
        case Light::Green:  cout << "Next: green (go)\n"; break;
        case Light::Yellow: cout << "Next: yellow (slow down)\n"; break;
        case Light::Red:    cout << "Next: red (stop)\n"; break;
    }
    return 0;
}

Output

Answer