Java - Throw IllegalArgumentException on assignment

Question

I am working on a Java assignment in which I was given a set of guidelines, and asked to correctly write a program that calculates the daily calorie requirement for people who engage in light sports/exercise 1 – 3 days per week based on their gender, weight, height, and age.

One of the main points of the assignment is to learn the use of exceptions. I have written the code, and it compiles correctly. However, when run, I am always thrown my exception, even in the gender variable is set to F, f, M or m. Any hints are good hints, but I am wondering how to get this program off the ground.

For clarifying, all the comments are from the teacher, while all of the code is from me. I use the comments as a framework for my code. Also, you will notice through the teacher comments that I am supposed to have another thrown IllegalArugmentException regarding the other parameters in calculateCalories(). I have not done this yet, as I am still working on getting the gender portion correct.

import java.util.*;

//add class javadoc comment here
public class CalorieCalculator {

public static final double LIGHT_ACTIVITY_FACTOR = 1.375;
public static final int MALE_BMR_CONSTANT = 66;
public static final int FEMALE_BMR_CONSTANT = 655;
public static final double MALE_WEIGHT_COEFFICIENT = 6.23;
public static final double FEMALE_WEIGHT_COEFFICIENT = 4.35;
public static final double MALE_HEIGHT_COEFFICIENT = 12.7;
public static final double FEMALE_HEIGHT_COEFFICIENT = 4.7;
public static final double MALE_AGE_COEFFICIENT = 6.8;
public static final double FEMALE_AGE_COEFFICIENT = 4.7;

//Prompt the user for gender (m,f,M,F), weight(lbs, double),
//height(inches, integer), and age(yrs, integer).
//You can assume the user will type in a number for weight
//and an integer for height and age - it is okay if the
//program crashes if they don't.
//Pass the user supplied values to the
//calculateCalories() method and output the returned daily calorie
//requirement (with descriptive text).

public static void main(String[] args) {
    Scanner console = new Scanner(System.in);

    System.out.print("Please enter your gender: ");
    String gender1 = console.next();
    System.out.print("Please enter your weight in pounds: ");
    double weight1 = console.nextDouble();
    System.out.print("Please enter your height in inches: ");
    int height1 = console.nextInt();
    System.out.print("Please enter your age in years: ");
    int age1 = console.nextInt();

    calculateCalories(gender1, weight1, height1, age1);


    System.out.println("Women:");
    System.out.println("Daily Calorie Requirement for Light Activity = " + (calculateCalories(gender1, weight1, height1, age1)));

}


//Throw an IllegalArgumentException if gender is not
//"f", "F", "m", or "M" or if any of the other parameters
//are not greater than 0. The exception message should
//explain the error.
//Use the formulas given below to calculate and return 
//the daily calorie requirement.

public static double calculateCalories(String gender, double weight, int height, int age) {
    if (gender.toLowerCase() != "m" || gender.toLowerCase() != "f") {
        throw new IllegalArgumentException("Please enter either M, F, m, or f");
    } else {

        if (gender == "f" || gender == "F") {
            double bmrFemale = (FEMALE_BMR_CONSTANT + (FEMALE_WEIGHT_COEFFICIENT * weight) + (FEMALE_HEIGHT_COEFFICIENT * height) - (FEMALE_AGE_COEFFICIENT * age));
            return LIGHT_ACTIVITY_FACTOR * bmrFemale; 
        } else {
            double bmrMale = (MALE_BMR_CONSTANT + (MALE_WEIGHT_COEFFICIENT * weight) + (MALE_HEIGHT_COEFFICIENT * height) - (MALE_AGE_COEFFICIENT * age));
            return LIGHT_ACTIVITY_FACTOR * bmrMale;
        }
    }

}

Don't compare String values using `==`. Use `equals()`. – Alexis C. Feb 15 '14 at 20:29 — Alexis C., Feb 15 '14 at 20:29
http://stackoverflow.com/q/513832/438992 – Dave Newton Feb 15 '14 at 20:30 — Dave Newton, Feb 15 '14 at 20:30
Thank you to both of you. Very good insight. – Rivers31334 Feb 15 '14 at 20:36 — Rivers31334, Feb 15 '14 at 20:36

score 1 · Accepted Answer · answered Feb 15 '14 at 20:36

first you need to use .equal instead of == in your conditions , second the first condition should be ith && not ||

so it will look like this

if (!gender.toLowerCase().equal("m") && !gender.toLowerCase().equal("f") {
        throw new IllegalArgumentException("Please enter either M, F, m, or f");

Java - Throw IllegalArgumentException on assignment

1 Answers1