Bob D February 2016

toString and booleans

I am making a class for a lightbulb and I have to have it be on/off state whether it's burntout or not, and its color. For whatever reason I get the right things to switch but, my toString prints the wrong answer and I cannot figure out why. I am not used to working with booleans and so my code may not support my logic. Can someone help?

Here is the code:

public class Light
 // Variables that will be initialized in the Light constructors.

 private boolean on;
 private boolean burntOut;
 private String color = "";

 // Default constructor that sets the bulb to on, not burnt out, and "white".

 public Light()
  on= true;
  burntOut = false;
  color = "white";

 // This constructor sets the variable "on" to the parameter o. The burntOut
 // variable is set to the parameter b. If burntOut
 // is true, on is set to false, no matter what value is stored in o.
 // The color variable is set to the parameter c only if c is "red", "green"
 // or "blue". The constructor ignores the case of the value in c. If c holds
 // any value other than "red", "green" or "blue", the constructor sets
 // color to "white".

 public Light(boolean o, boolean b, String c)
on = o;
    on = false;
    on= o;
    color = "red"; 
    color = "blue";
  if (c.equalsIgnoreCase("green")){
  else {
    color = "white";


 // The toString method returns a String with the Light in the format:
 // off red    burnt out
 // on green    not burnt out
 // Notice there is one space between "off"/"on" and the value for color,
 // and a tab before the "burnt out" or "not burnt out".

 public String toString()
  String x ="";
       if(on = true){
         x+="on" + " ";
       if(on = false){
         x+= "off" + " ";

       x+= color;

       if (burntOut = false){
         x+="\t" + "not burnt ou        


David February 2016


if(on = true){

You're not comparing, you're assigning the value. To compare, use ==:

if(on == true){

Or, even simpler:


(Note: There are several places in your code which have this error. This is illustrating only one of them. Fix the others accordingly as well.)

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Asked in February 2016
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