Basic Java Program Help (Target-Heart-Rate Calculator)

RoRo979

sorry to intrude on this thread but i dont know where else to ask for help could someone please help me with this problem, (Target-Heart-Rate Calculator) While exercising, you can use a heart-rate monitor to see
that your heart rate stays within a safe range suggested by your trainers and doctors. According to the
American Heart Association (AHA) (www.americanheart.org/presenter.jhtml?identifier=4736),
the formula for calculating your maximum heart rate in beats per minute is 220 minus your age in
years. Your target heart rate is a range that’s 50–85% of your maximum heart rate. [Note: These formulas
are estimates provided by the AHA. Maximum and target heart rates may vary based on the
health, fitness and gender of the individual. Always consult a physician or qualified health care professional
before beginning or modifying an exercise program.] Create a class called HeartRates. The
class attributes should include the person’s first name, last name and date of birth (consisting of separate
attributes for the month, day and year of birth). Your class should have a constructor that receives
this data as parameters. For each attribute provide set and get methods. The class also should
include a method that calculates and returns the person’s age (in years), a method that calculates and
returns the person’s maximum heart rate and a method that calculates and returns the person’s target
heart rate. Write a Java application that prompts for the person’s information, instantiates an object
of class HeartRates and prints the information from that object—including the person’s first name,
last name and date of birth—then calculates and prints the person’s age in (years), maximum heart
rate and target-heart-rate range. im sorry for this, i have all the code working but the target heart rate as it cannot return a double for me it is round it thus e.g im 16, maximum HR is 204, it should go, 204/100*50, but when 204/100 = 2 not 2.04.

RoRo979

sorry to intrude on this thread but i dont know where else to ask for help could someone please help me with this problem, (Target-Heart-Rate Calculator) While exercising, you can use a heart-rate monitor to see
that your heart rate stays within a safe range suggested by your trainers and doctors. According to the
American Heart Association (AHA) (http://www.americanheart.org/present...dentifier=4736),
the formula for calculating your maximum heart rate in beats per minute is 220 minus your age in
years. Your target heart rate is a range that’s 50–85% of your maximum heart rate. [Note: These formulas
are estimates provided by the AHA. Maximum and target heart rates may vary based on the
health, fitness and gender of the individual. Always consult a physician or qualified health care professional
before beginning or modifying an exercise program.] Create a class called HeartRates. The
class attributes should include the person’s first name, last name and date of birth (consisting of separate
attributes for the month, day and year of birth). Your class should have a constructor that receives
this data as parameters. For each attribute provide set and get methods. The class also should
include a method that calculates and returns the person’s age (in years), a method that calculates and
returns the person’s maximum heart rate and a method that calculates and returns the person’s target
heart rate. Write a Java application that prompts for the person’s information, instantiates an object
of class HeartRates and prints the information from that object—including the person’s first name,
last name and date of birth—then calculates and prints the person’s age in (years), maximum heart
rate and target-heart-rate range. im sorry for this, i have all the code working but the target heart rate as it cannot return a double for me it is round it thus e.g im 16, maximum HR is 204, it should go, 204/100*50, but when 204/100 = 2 not 2.04.

RoRo979

import java.util.Scanner;
public class test {
Scanner ronan = new Scanner(System.in);
private int day;
private int month;
private int year;
private String first;
private String last;
private int maximum;
private int number;
private int higher;
private int lower;
private int total;
private int age;

public test(String first, String last, int day, int month, int year){
this.day = day;
this.month = month;
this.year= year;
this.first=first;
this.last=last;
}
public void setDate(int day, int month, int year){
this.day = day;
this.month = month;
this.year= year;
}
public String getName(){
return first;
}
public String getName2(){
return last;
}
public int getDate(){
return day;
}
public int getMonth(){
return month;
}
public int getYear(){
return year;
}
public int age(){
age = 2013-year;
return age;
}
public int Maximum(){
number = 2013 - year;
total= 220 - number;
this.total= total;
return total;
}
public int HRH(){
total=220-age;
higher = total/100*50;
return higher;
}
public int HRL(){
total=220-age;
lower = total/100*85;
return lower;
}

}

Thats what i got

Unregistered.

You need to cast the division part (eg 204/100) to an integer.

KonFusion

You need to put some line breaks into that wall of text.

Helping you is a lot easier when people's eyes aren't bleeding :pac:

RoRo979

Unregistered. wrote: »

You need to cast the division part (eg 204/100) to an integer.

i dont think that would be the solution as i need the division anwer to be a double. e.g for the 85% part and im 16, it would divide 204 by 100, giving me 2.04, i need to then multiply this 2.04 by 85 which i would get 173.4. but the when i use the return on it it doesnt allow me, if the division became an int it would become 2 by 85 giving me 170

RoRo979

import java.util.Scanner;
public class test {
private int day;
private int month;
private int year;
private String first;
private String last;
private int maximum;
private int number;
private int higher;
private int lower;
private int total;
private int age;

public test(String first, String last, int day, int month, int year){
this.day = day;
this.month = month;
this.year= year;
this.first=first;
this.last=last;
}

public void setDate(int day, int month, int year){
this.day = day;
this.month = month;
this.year= year; }


public int age(){
age = 2013-year;
return age; }

public int Maximum(){
number = 2013 - year;
total= 220 - number;
this.total= total;
return total; }

public int HRH(){
total=220-age;
higher = total/100*50;
return higher; }


public int HRL(){
total=220-age;
lower = total/100*85;
return lower; }

}

is that easier to read
what i tried was,

public double HRL(){
total = 220-age;
double random = total/100; // 2.04
double lower = random * 85;
return lower;
}

and the errors follow thanks in advance for any help

Unregistered.

RoRo979 wrote: »

i dont think that would be the solution as i need the division anwer to be a double. e.g for the 85% part and im 16, it would divide 204 by 100, giving me 2.04, i need to then multiply this 2.04 by 85 which i would get 173.4. but the when i use the return on it it doesnt allow me, if the division became an int it would become 2 by 85 giving me 170

Cast the result to an integer! int result = (int) ((204/100) * 85 )

Marlay

RoRo979 wrote: »

im sorry for this, i have all the code working but the target heart rate as it cannot return a double for me it is round it thus e.g im 16, maximum HR is 204, it should go, 204/100*50, but when 204/100 = 2 not 2.04.

Not certain I follow you, but with this:

double random = total/100; // 2.04

you won't get a double result as you are dividing two integers. You would need to cast one of the operands to a double first:

double random = (double)total/100; // 2.04

Feathers

Translation:

RoRo979 wrote: »

Sorry to intrude on this thread but I don't know where else to ask for help

Could someone please help me with the problem below. I have all the code working except the target heart rate as it cannot return a double for me. It is rounding it thus:

E.g. I'm 16, maximum HR is 204, it should go: 204/100 * 50, but where 204/100 = 2 not 2.04.

Full instructions of the problem I'm working on:

Target-Heart-Rate Calculator

While exercising, you can use a heart-rate monitor to see that your heart rate stays within a safe range suggested by your trainers and doctors. According to the American Heart Association (AHA) , the formula for calculating your maximum heart rate in beats per minute is 220 minus your age in years.

Your target heart rate is a range that’s 50–85% of your maximum heart rate. [Note: These formulas are estimates provided by the AHA. Maximum and target heart rates may vary based on the health, fitness and gender of the individual. Always consult a physician or qualified health care professional before beginning or modifying an exercise program.]

Create a class called HeartRates:

Attributes

The class attributes should include the person's:

• first name
• last name
• date of birth (consisting of separate attributes for the month, day and year of birth).

Methods

• Your class should have a constructor that receives this data as parameters.
• For each attribute provide set and get methods.

The class also should include:

• a method that calculates and returns the person’s age (in years)
• a method that calculates and returns the person’s maximum heart rate
• a method that calculates and returns the person’s target heart rate.

Write a Java application that prompts for the person’s information, instantiates an object of class HeartRates and prints the information from that object— including the person’s first name, last name and date of birth — then calculates and prints the person’s age in (years), maximum heart rate and target-heart-rate range.

The code I have so far:

import java.util.Scanner;
public class test {
    Scanner ronan = new Scanner(System.in);
    private int day;
    private int month;
    private int year;
    private String first;
    private String last;
    private int maximum;
    private int number;
    private int higher;
    private int lower;
    private int total;
    private int age;
    
    public test(String first, String last, int day, int month, int year){
        this.day = day;
        this.month = month;
        this.year= year;
        this.first=first;
        this.last=last;
    }
    public void setDate(int day, int month, int year){
        this.day = day;
        this.month = month;
        this.year= year;    
    }
    public String getName(){
        return first;
    }
    public String getName2(){
        return last;
    }
    public int getDate(){
        return day;
    }
    public int getMonth(){
        return month;
    }
    public int getYear(){
        return year;
    }
    public int age(){
        age = 2013-year;
        return age;    
    }
    public int Maximum(){
        number = 2013 - year;
        total= 220 - number;
        this.total= total;
        return total;
    }
    public int HRH(){
        total=220-age;
        higher = total/100*50;
        return higher;
    }
    public int HRL(){
        total=220-age;
        lower = total/100*85;
        return lower;
    }

}

OP, if you're able to learn Java, BB code formatting shouldn't be too much trouble

RoRo979

i tried setting one as double but it didnt work, i also tried casting one as an int but it didnt work, im unsure if im typing it incorrectly but im getting an error each time.

Wetai

If it's anything like C#, and I'm remembering correctly, it's the denominator (maybe both) that needs to be a double. Have you tried that? Can't hurt if you haven't.

Also, if your function returns an int, no matter what you change (other than the signature (return type)), you'll still get an int.

Unregistered.

public int HRH(){
total=220-age;
higher = (int) (total/100) * 50;
return higher;
}

If you want accuracy then just use doubles for your calculations then round them to ints.

RoRo979

java.util.IllegalFormatConversionException: d != java.lang.Double
at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source)
at java.util.Formatter$FormatSpecifier.printInteger(Unknown Source)
at java.util.Formatter$FormatSpecifier.print(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.io.PrintStream.format(Unknown Source)
at java.io.PrintStream.printf(Unknown Source)
at testmain.main(testmain.java:9)

^^^^^^
That is the error;

System.out.printf("ideal HR is %d-%d", ro.HRH(),ro.HRL());

^^^^
line 9 in testmain

RoRo979

haha im really sorry if im making some basic mistake, i just started learning java and i just want to understand my errors and try learn from them.

Wetai

Try changing those functions' return type to double (public double ...). %d in the printf is expecting doubles and getting integers.

Feathers

RoRo979 wrote: »

i tried setting one as double but it didnt work, i also tried casting one as an int but it didnt work, im unsure if im typing it incorrectly but im getting an error each time.

What code did you try and what's the error you're getting? (Please use "code" tags to wrap both).

EDIT: sorry, just saw your post. I'd be inclined to remove the use of the formatter for now & get the logic working first.

RoRo979

haha so whenever i seem to change anything to a double i get an error haha

RoRo979

if someone wouldnt mind could you post some code that will work as i think i may be doing it wrong, thanks

mad turnip

RoRo you really need to post ALL THE CODE. This includes your public static void main(

As thats were the errors seem to lie

RoRo979

public class testmain {

    public static void main(String[] args) {
        Scanner imput= new Scanner(System.in);
        test ro = new test("name1", "name2", 28, 8, 1997);
        System.out.printf("Name:%s %s\nDOB: %d/%d/%d\n age:%d\n", ro.getName(), ro.getName2(),ro.getDate(), ro.getMonth(),ro.getYear(), ro.age());
        System.out.printf("your maximum HR is %d\n", ro.Maximum());
        System.out.printf("ideal HR is %d-%d", ro.HRH(),ro.HRL());
    }

}

apologies should of done that at the start

mad turnip

RoRo979 wrote: »

public class testmain {

    public static void main(String[] args) {
        Scanner imput= new Scanner(System.in);
        test ro = new test("name1", "name2", 28, 8, 1997);
        System.out.printf("Name:%s %s\nDOB: %d/%d/%d\n age:%d\n", ro.getName(), ro.getName2(),ro.getDate(), ro.getMonth(),ro.getYear(), ro.age());
        System.out.printf("your maximum HR is %d\n", ro.Maximum());
        System.out.printf("ideal HR is %d-%d", ro.HRH(),ro.HRL());
    }

}

apologies should of done that at the start

can you post all your current code as what i'm running has no problems with this output:

Name:name1 name2
DOB: 28/8/1997
age:16
your maximum HR is 204
ideal HR is 100-170

Edit:

Oh i see now you want to change one to a double?

Where your using %d this stands for an int
If you want to change any of these values to a double or a float use %f instead this should resolve your issue.

If you want some more information on the decimal system of using %f you can check out this link:
http://docs.oracle.com/javase/tutorial/java/data/numberformat.html

Username99

public class HeartRates
{
private String firstName;
private String lastName;
private int day;
private int month;
private int year;
private int currentYear = 2013;


public HeartRates ( String fName, String lName, int fDay, int fMonth, int fYear, int cYear)
{
firstName = fName;
lastName = lName;
day = fDay;
month = fMonth;
year = fYear;
currentYear = cYear;
}//end of constructor

public void setFirstName( String fName )
{
firstName = fName;
}//end of method setFirstName

public String getFirstName()
{
return firstName;
}//end of method getFirstName

public void setLastName( String lName )
{
lastName = lName;
}//end of method getLastName

public String getLastName()
{
return lastName;
}//end of method getLastName

public void setDay( int fDay )
{
day = fDay;
}//end of method setDay

public int getDay()
{
return day;
}//end of method getDay

public void setMonth( int fMonth )
{
month = fMonth;
}//end of method setMonth

public int getMonth()
{
return month;
}//end of method getMonth

public void setYear( int fYear )
{
year = fYear;
}//end of method setYear

public int getYear()
{
return year;
}//end of method getYear


public int getAgeInYears()
{
return ( currentYear - year );
}//end of method age in years


public int getMaxHeartRate()
{
return (220 - getAgeInYears() );
}

public int targetHeartRateMin()
{
return (( getMaxHeartRate() / 100 ) * 50 );
}

public int targetHeartRateMax()
{
return (( getMaxHeartRate() / 100 ) * 85 );
}


}//end of class HeartRates

Username99

import java.util.Scanner;

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

HeartRates object1HeartRates = new HeartRates ( "John", "BonJovi", 09, 02, 1988, 2013 );

//start of first name user prompt
System.out.print( "Please enter your first name: " );
//end of first name user prompt

//store the user input in the variable called hoanName
String hoanName = input.next();

//call the setFirstName method from the HeartRates and pass hoanName to it
object1HeartRates.setFirstName( hoanName );

System.out.printf( "The first name you entered is: %s", object1HeartRates.getFirstName() );

//start of last name user prompt
System.out.print( "\nPlease enter your last name: " );
//end of last name user prompt

//store the user input in the variable called adoName
String adoName = input.next();

//call the setLastName method from the HeartRates and pass adoName to it
object1HeartRates.setLastName( adoName );

System.out.printf( "The last name you entered is: %s", object1HeartRates.getLastName() );

System.out.print( "\nPlease enter the day of your birth: " );
int dayOfBirth = input.nextInt();
object1HeartRates.setDay( dayOfBirth );

System.out.printf( "You entered your day of birth as: %s", object1HeartRates.getDay() );

System.out.print( "\nPlease enter the month of your birth: " );
int monthOfBirth = input.nextInt();
object1HeartRates.setMonth( monthOfBirth );

System.out.printf( "You entered your month of birth as: %s", object1HeartRates.getMonth() );

System.out.print( "\nPlease enter the year of your birth: " );
int yearOfBirth = input.nextInt();
object1HeartRates.setYear( yearOfBirth );

System.out.printf( "You entered your year of birth as: %s", object1HeartRates.getYear() );

int ageYears = object1HeartRates.getAgeInYears();

System.out.printf( "\nYou are " + ageYears + " years old." );

System.out.printf( "\nYour max heart rate is " + object1HeartRates.getMaxHeartRate() + "." );





}//end of main method
}//end of class HeartRatesTest

RoRo979

hi Username99 thanks that was very helpful, just one question, for the target heart rate i am still receiving errors, here is the code i entered

System.out.printf("\nYour target heart rate is %f - %f\n",targetHeartRateMin(), targetHeartRateMin());

I also tried doing

System.out.printf("\nYour target is %d- %d\n",targetHeartRateMin(), targetHeartRateMin());

but neither seemed to work, how would you go about gettin this, thank you

Unregistered.

RoRo979 wrote: »

hi Username99 thanks that was very helpful, just one question, for the target heart rate i am still receiving errors, here is the code i entered

System.out.printf("\nYour target heart rate is %f - %f\n",[B]targetHeartRateMin()[/B], [B]targetHeartRateMin()[/B]);

I also tried doing

System.out.printf("\nYour target is %d- %d\n",[B]targetHeartRateMin()[/B], [B]targetHeartRateMin()[/B]);

but neither seemed to work, how would you go about gettin this, thank you

What seems to be the problem? (Note what I have highlighted in bold)

RoRo979

the return value is coming up null- null?

Unregistered.

RoRo979 wrote: »

the return value is coming up null- null?

What IDE are you using? It would be worth learning to use a debug tool for this.

If the result is null, then this is beyond what you have asked help for. There is likely some small changed you have made, perhaps a variable is uninitialized, but without knowing the changes you have made, we can't see that.
Post your most up-to-date code. Leave out the getters and setters, we don't need to see them.

RoRo979

ok so i have the code that Username99 put up. i only added in

System.out.printf("\nYour target is %f - %f\n",targetHeartRateMin(), targetHeartRateMin());

which i expected to run fine but an error is coming up saying that

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
	The method targetHeartRateMin() is undefined for the type testmain
	The method targetHeartRateMax() is undefined for the type testmain

i am really confused as to why it is not recognising this method but recognises all the rest.

i am currently using eclipse.

RoRo979

right hahah i have discovered that error. i just wrote

targetHeartRateMin()

instead of

object1HeartRates.targetHeartRateMin()

but another error now comes up haha. it reads

xception in thread "main" java.util.IllegalFormatConversionException: f != java.lang.Integer
	at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source)
	at java.util.Formatter$FormatSpecifier.printFloat(Unknown Source)
	at java.util.Formatter$FormatSpecifier.print(Unknown Source)
	at java.util.Formatter.format(Unknown Source)
	at java.io.PrintStream.format(Unknown Source)
	at java.io.PrintStream.printf(Unknown Source)
	at testmain.main(testmain.java:59)

Unregistered.

RoRo979 wrote: »

right hahah i have discovered that error. i just wrote

targetHeartRateMin()

instead of

object1HeartRates.targetHeartRateMin()

but another error now comes up haha. it reads

xception in thread "main" java.util.IllegalFormatConversionException: f != java.lang.Integer
    at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source)
    at java.util.Formatter$FormatSpecifier.printFloat(Unknown Source)
    at java.util.Formatter$FormatSpecifier.print(Unknown Source)
    at java.util.Formatter.format(Unknown Source)
    at java.io.PrintStream.format(Unknown Source)
    at java.io.PrintStream.printf(Unknown Source)
    at testmain.main(testmain.java:59)

READ THE ERROR! You changed %d to %f. %f is for double, %d is for ints. You changed it from %d to %f and and your function returns an int. That is what this is telling you.

RoRo979

i changed %f to %d but i am still getting an error,

Exception in thread "main" java.util.MissingFormatArgumentException: Format specifier 'd'
	at java.util.Formatter.format(Unknown Source)
	at java.io.PrintStream.format(Unknown Source)
	at java.io.PrintStream.printf(Unknown Source)

Unregistered.

RoRo979 wrote: »

i changed %f to %d but i am still getting an error,

Exception in thread "main" java.util.MissingFormatArgumentException: Format specifier 'd'
    at java.util.Formatter.format(Unknown Source)
    at java.io.PrintStream.format(Unknown Source)
    at java.io.PrintStream.printf(Unknown Source)

Ok, stop using printf until you have verified that the original problem is solved. Just use println. You can go back to printf later if you want, but you asked for help with the logic on your code, this goes beyond that.

RoRo979

really from where i started off I am now a few steps back haha originally i was looking for a precise target heart rate as i was only getting 170 instead of 173 with a double.

RoRo979

hahaha oh how java is challenging right so i fixed that error and i have just discovered that i am back to where i was at the start just with different code. i am looking for the target heart range to be precise.

Unregistered.

RoRo979 wrote: »

hahaha oh how java is challenging right so i fixed that error and i have just discovered that i am back to where i was at the start just with different code. i am looking for the target heart range to be precise.

Did you not read about casting as was mentioned earlier?


This is the soution:
int result = (int) (( (double) 204/100) *85) ;


Breakdown:


((double) 204/100) // result of the division will be a double, eg 2.04


(int) ( (double) 204/100) *85) // the result of everything in the brackets will be an int.

So even though 2.04 * 85 = 173.4 inside the brackets, casting means that this is transformed to an integer, which is 173.

RoRo979

ahhhh it works now hahaha, i did read it and i tried it but an error came up every time, yessss, thank you soo much. I am exremely grateful for all the help you all gave me :):)