How do I do an if else statement that loops over an array of strings?

Question

I am basically writing a virtual zoo. I have an animal class which contains an array called eats which contains strings of foods. I have other classes, such as lion and tiger which extend my animal class. Within these classes I have specified what food they eat as this is unique for each animal. For example, a lion eats steak and celery. I have now been asked to create a canEat() method in my animal class which basically returns true if that particular animal can eat that food. How would I go about doing this?

Here is my animal class

public abstract class Animal {
    String[] eats = new String[] {"steak", "celery", "fish", "fruit"};

    public boolean canEat() {

    }
}

and here is how I specify what each specific animal can eat in their respected class

public class Lion extends Animal {
     public Lion (String[] eats) {
          super(new String[] {"steak", "celery"});
     }
}

Thanks in advance, I hope I explained this clearly

public boolean canEat() { needs to be past something before you can make a check, something like public boolean canEat(String food) { — MadProgrammer
– MadProgrammer, Commented Dec 9, 2015 at 0:17

Mohammed Aouf Zouag · Accepted Answer · 2015-12-09 00:30:57Z

2

Define the canEat method as follows:

public boolean canEat(String food) {
    return Arrays.asList(eats).contains(food);
}

Here is how you can use it:

public static void main(String args[]) {
    Lion lion = new Lion(new String[] {"steak", "meat", "otherFood"});

    System.out.println("Can the lion eat steak ? " + lion.canEat("steak"));
    // System.out: Can the lion eat steak ? true

    System.out.println("Can the lion eat meat loaf ? " + lion.canEat("meat loaf"));
    // System.out: Can the lion eat meat loaf ? false
}

edited Dec 9, 2015 at 0:30

answered Dec 9, 2015 at 0:17

Mohammed Aouf Zouag

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Comments

Avalanche · Accepted Answer · 2015-12-09 00:19:10Z

0

Many ways to solve this, using a for loop:

public boolean canEat(String food) {
    for (int i = 0; i < eats.length; i++) {
        if (eats[i].equals(food))
            return true;
    }
    return false;
}

answered Dec 9, 2015 at 0:19

Avalanche

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Comments

MadProgrammer · Accepted Answer · 2015-12-09 00:21:28Z

0

You'll need to change one of your classes slightly, for example, you could do something like...

public abstract class Animal {
    String[] eats;

    public Animal(String[] canEat) {
        eats = canEat;
    }

    public boolean canEat(String food) {
        boolean canEat = false;
        for (String eatiable :eats) {
            if (eatiable.equals(food)) {
                canEat = true;
                break;
            }
        }
        return canEat;
    }
}

Equally, you could make canEat abstract and make the child classes deal with it.

This does a case-sensitive comparison, if you need to a case-insensitive comparison, you could use eatiable.equalsIgnoresCase(food) instead

answered Dec 9, 2015 at 0:21

community wiki

MadProgrammer

Comments

v.ladynev · Accepted Answer · 2015-12-09 00:22:26Z

0

So full answer can be

public abstract class Animal {
    private String[] eats;

public Animal(String[] eats) {
    this.eats = eats;
}

public boolean canEat(String food) {
    return Arrays.asList(eats).contains(food);
}

}

public class Lion extends Animal {
     public Lion (String[] eats) {
          super(eats);
     }
}

answered Dec 9, 2015 at 0:22

v.ladynev

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Comments

Raf · Accepted Answer · 2015-12-09 00:24:58Z

0

You could convert your array to List of Strings as List<String> and then check if list contains the food (passed as argument to canEat). Modify your canEat to as follow

public boolean canEat(String food) {
    List<String> eatsList = Arrays.asList(eats); 
    //if(eatsList.contains(food)) { 
    //   return true; 
    //} else {
    //  return false; 
    //}

    //as pointed out in comments would do exactly as above four lines of code
    return eatsList.contains(food); 
}

Then when you create object you invoke canEat() and pass it the food as argument.

lion.canEat("fish");

edited Dec 9, 2015 at 0:24

answered Dec 9, 2015 at 0:17

Raf

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5 Comments

Yassin Hajaj Over a year ago

A bit redundant don't you think? :)

Raf Over a year ago

I know but, I wasn't sure if he is allowed to use List or not. That's why I showed him how to convert array to List.

Yassin Hajaj Over a year ago

Not about the list part, but about the return :D Look again :p

MadProgrammer Over a year ago

@Raf No, they mean you could just do return eatsList.contains(food) the if-else statement is redundant

Raf Over a year ago

Now I see what you are talking about. I am getting there slowly. Thanks for pointing out though.

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