1. Member
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Apr 2010
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Hello all, I am new to this forum, and also to java, so bear with me a bit.
I got this exercise in lab class to make a program that converts from one type of temperature to the other two(eg. Celsius to farenheit and kelvin). Now, I was progressing along nicely, and managed to make the first one(for Celsius) work, however Farenheit and Kelvin converters don't work. I asked my lab helper what was wrong, and he was stumped. The IDE(netbeans 6.8) isn't showing any underlined red errors, so I hope someone here could help me.

Java Code:
```import java.io.*;

public class Main
{

public static void main(String[] args) throws IOException
{
System.out.println("Ingrese la medida de temperature que quiere convertir(1: Celsius, 2: Farenheit, 3:Kelvin): ");

{
System.out.print("Ingrese la temperatura Celsius que quiere convertir: ");

double kelvinC = c + 273.15;
double farenheitC = 1.8*c + 32;

System.out.print("La temperatura "+c+"°C es equivalente a "+farenheitC+"°F y "+kelvinC+"°K.");
}

{
System.out.println("Ingrese la temperatura Farenheit que quiere convertir: ");

double celsiusF=(f-32)/1.8;
double kelvinF=(f+459.67)/1.8;

System.out.print("La temperatura "+f+"°F es equivalente a "+celsiusF+"°C y "+kelvinF+"°K.");
}

{
System.out.println("Ingrese la temperatura Kelvin que quiere convertir: ");

double celsiusK=k-273.15;
double farenheitK=(9/5)*k - 459.67;

System.out.print("La temperatura "+k+"°K es equivalente a "+celsiusK+"°C y "+farenheitK+"°F");
}

}

}```
When it prompts me with "Ingrese la medida de temperature que quiere convertir(1: Celsius, 2: Farenheit, 3:Kelvin): ", any answer other than 1 gives me this error:

Exception in thread "main" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Num berFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:470)
at java.lang.Integer.parseInt(Integer.java:499)
at laboratorio1.Main.main(Main.java:32)
Java Result: 1
BUILD SUCCESSFUL (total time: 14 seconds)

I hope someone can help me, thanks in advance.

2. Originally Posted by Umogrim
Java Code:
```import java.io.*;

public class Main
{

public static void main(String[] args) throws IOException
{
System.out.println("Ingrese la medida de temperature que quiere convertir(1: Celsius, 2: Farenheit, 3:Kelvin): ");

{
System.out.print("Ingrese la temperatura Celsius que quiere convertir: ");

double kelvinC = c + 273.15;
double farenheitC = 1.8*c + 32;

System.out.print("La temperatura "+c+"°C es equivalente a "+farenheitC+"°F y "+kelvinC+"°K.");
}

{
System.out.println("Ingrese la temperatura Farenheit que quiere convertir: ");

double celsiusF=(f-32)/1.8;
double kelvinF=(f+459.67)/1.8;

System.out.print("La temperatura "+f+"°F es equivalente a "+celsiusF+"°C y "+kelvinF+"°K.");
}

{
System.out.println("Ingrese la temperatura Kelvin que quiere convertir: ");

double celsiusK=k-273.15;
double farenheitK=(9/5)*k - 459.67;

System.out.print("La temperatura "+k+"°K es equivalente a "+celsiusK+"°C y "+farenheitK+"°F");
}

}

}```
A few corrections:

1) Delete all of these lines in your if-statements; they're useless:

Java Code:
`            new BufferedReader(new InputStreamReader(System.in));`

Java Code:
```        BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Ingrese la medida de temperature que quiere convertir(1: Celsius, 2: Farenheit, 3:Kelvin): ");

int choice= Integer.parseInt(line);```
... and change your ifs to this:

Java Code:
```if (choice == 1) { ... }
else if (choice == 2) { ... }
else if (choice == 3) { ... }```
kind regards,

Jos

3. Member
Join Date
Apr 2010
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Thanks a bunch JosAH! That did the trick. You really saved me(and my lazy partner) on this one.

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