41 lines
1006 B
Java
41 lines
1006 B
Java
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//: enumerated/TrafficLight.java
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// Enums in switch statements.
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import static net.mindview.util.Print.*;
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// Define an enum type:
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enum Signal { GREEN, YELLOW, RED, }
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public class TrafficLight {
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Signal color = Signal.RED;
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public void change() {
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switch(color) {
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// Note that you don't have to say Signal.RED
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// in the case statement:
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case RED: color = Signal.GREEN;
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break;
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case GREEN: color = Signal.YELLOW;
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break;
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case YELLOW: color = Signal.RED;
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break;
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}
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}
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public String toString() {
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return "The traffic light is " + color;
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}
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public static void main(String[] args) {
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TrafficLight t = new TrafficLight();
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for(int i = 0; i < 7; i++) {
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print(t);
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t.change();
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}
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}
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} /* Output:
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The traffic light is RED
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The traffic light is GREEN
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The traffic light is YELLOW
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The traffic light is RED
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The traffic light is GREEN
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The traffic light is YELLOW
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The traffic light is RED
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*///:~
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