Is there a reason that my comparison operators are not following the logic behind them

Question

Logically I believe that when I run my code anyone between 0 and 11 should be assigned ageGroup = children, 12 to 19 should be ageGroup = teenager, 20 to 31 ageGroup = young adult, and 31+ ageGroup = adult. I've tried different things such as if (age < 0 && age > 11) but that returns the same results. Basically my question is am I using the logical operators correctly for what I am trying to do?

import java.util.ArrayList;
import java.util.List;

public class Person implements Comparable<Person> {
    private String name;
    private int age;
    private String ageGroup;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;

        if (name == null || name == "") {
            throw new IllegalArgumentException("name cannot be null or empty");
        }

        if (age < 0) {
            throw new IllegalArgumentException("age cannot be negative");
        }


        List<String> inList = new ArrayList<>();
        if (age == 0 && age <= 11) {
            ageGroup = "children";
        } else if (age == 12 || age <= 19) {
            ageGroup = "teenagers";
        } else if (age == 20 || age <= 31) {
            ageGroup = "young adults";
        } else if (age >= 32) {
            ageGroup = "adults";
        }
        inList.add(ageGroup);

    }



    @Override
    public int compareTo(Person o) {
        if (age < o.age) {
            return -1;
        } else {
            if (age > o.age) {
                return 1;
            } else {
                return name.compareTo(o.name);
            }

        }

    }

    @Override
    public boolean equals(Object o) {
        if (o != null) {
            if (o == this) {
                return true;
            }
            if (getClass() == o.getClass()) {
                Person other = (Person) o;
                if (compareTo(other) == 0) {
                    return true;
                }
            }
        }
        return false;

    }

    @Override
    public String toString() {

        return String.format(
            "Person [name=%s,age=%d,group=%s]",
            name, age, ageGroup);

    }

}

This code is supposed to return [name=Fiona,age=0,group=children] but it returns [name=Fiona,age=11,group=teenagers]

`name == ""` - See: [How do I compare Strings in Java?](https://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — Jacob G., Nov 13 '19 at 03:46
This condition `age == 0 && age <= 11`, is always false for anything more than 0 — Thiyagu, Nov 13 '19 at 03:47

Jason · Accepted Answer · 2019-11-13T05:19:24.997

2

All of your comparisons of age start with something like:

age == n ||

They should be:

age >= n &&

You can simplify your logic and drop the lower bound checking:

if (age <= 11) {
    ageGroup = "children";
} else if (age <= 19) {
    ageGroup = "teenagers";
} else if (age <= 31) {
    ageGroup = "young adults";
} else {
    ageGroup = "adults";
}

This works because once a condition is met, the corresponding block is executed, and the rest of the else statements are ignored.

edited Nov 13 '19 at 05:19

answered Nov 13 '19 at 03:42

Jason

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They initially were all in the `age >= 0` format but I changed it up trying to find answers that were unsuccessful. Thank you so much – sprinty200 Nov 13 '19 at 04:20
Yes, but you also want to use `&&` instead of `||` if you're going to use `>=`. – Dawood ibn Kareem Nov 13 '19 at 04:32
@Jason I was actually talking to sprinty200, not to you. Your answer was perfectly fine - I even upvoted it; and upvoting answers is something I don't do terribly often. – Dawood ibn Kareem Nov 13 '19 at 05:17
@DawoodsaysreinstateMonica I see exactly what you mean, thank you for the response – sprinty200 Nov 13 '19 at 15:11

Is there a reason that my comparison operators are not following the logic behind them

1 Answers1