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+---- Thread: [Java] Calculator || + - * / || No gui (/showthread.php?tid=4730078)
Calculator || + - * / || No gui - Captain Steve Rogers - Mar 14, 2015
Made my first Calculator in Java without copying 🤗 🤗 🤗
Next step : With GUI
Please give me some homework( little easy please still beginner )
Source Code :
Code
import java.util.Scanner;
public class Basics
{
public static void main(String[] args)
{
Scanner obj = new Scanner(System.in);
int a;
System.out.println("1. Addition\n2. Subtraction \n3. Multiplication\n4. Division");
System.out.print("Choose any one and enter the number : ");
a=obj.nextInt();
if(a < 1 || a > 4)
{
System.out.println("Invalid choice");
System .exit( 0 );
}
else
System.out.print("Enter 1st number : ");
int b=obj.nextInt();
System.out.print("Enter 2nd number : ");
int c=obj.nextInt();
switch(a)
{
case 1:
{
System.out.println("Addition is "+(b+c));
break;
}
case 2:
{
System.out.println("Subtraction is "+(b-c));
break;
}
case 3:
{
System.out.println("Multiplication is "+(b*c));
break;
}
case 4:
{
System.out.println("Division is "+(b/c));
break;
}
}
}
}Output :
![[Image: fab84b7deda1b5746992f7b51f44c9e0.png]](https://i.gyazo.com/fab84b7deda1b5746992f7b51f44c9e0.png)
Special thanks to Viviparous.
* - La Manifesto - Mar 14, 2015
It looks nice so far. Have you ever done GUI before? That would be a interesting next step to try and do.
* - Captain Steve Rogers - Mar 14, 2015
(Mar 14, 2015 10:24 AM)Viviparous Wrote: It looks nice so far. Have you ever done GUI before? That would be a interesting next step to try and do.
Thanks, yes i have done GUI before like 5 months ago.
I have done Core & Adv Java in college and in institution but still i was not able to code anything before 1 week ago.
Started taking Java seriously.
Yup :)
* - La Manifesto - Mar 14, 2015
Try and make it into a GUI and see if you can do it. Then try doing some more advance concepts in Java.
* - Captain Steve Rogers - Mar 14, 2015
(Mar 14, 2015 10:32 AM)Viviparous Wrote: Try and make it into a GUI and see if you can do it. Then try doing some more advance concepts in Java.
Thanks a lot mate 🤝
Finally code done of non gui calculator ✌
* - csrk - Mar 16, 2015
Nicely done for a beginner. Let me throw you some tips? :-)
Generally switch-case code is smelly, if you want to add more methods (methods like add/mul/sin/cosine etc etc etc) you have to go back and edit code you know already words. Better to create methods and just implement a new method.
Speaking of methods, in this case your calculator works perfectly fine using only a main method, but it'd be alot prettier if you created methods for each calculation, like public int add(int a, int b); and so on.
Also, it'd probably be easier if you had a classed called RatNum or something that holds a numerator and a denominator int, and you use those for the calculations.
* - Iponu - Mar 16, 2015
Cool I remember that was the first program I wrote to.. People keep saying try write it in gui. Me personally I would tell you to stay away from it a bit, until you learn more about java classes, interfaces, arrays, arraylists, etc... Otherwise you will be tempted use a program that makes the gui for you rather than actually learning how to code it without a visual.
* - Captain Steve Rogers - Mar 16, 2015
(Mar 16, 2015 05:12 AM)Rewbert Wrote: Nicely done for a beginner. Let me throw you some tips? :-)
Generally switch-case code is smelly, if you want to add more methods (methods like add/mul/sin/cosine etc etc etc) you have to go back and edit code you know already words. Better to create methods and just implement a new method.
Speaking of methods, in this case your calculator works perfectly fine using only a main method, but it'd be alot prettier if you created methods for each calculation, like public int add(int a, int b); and so on.
Also, it'd probably be easier if you had a classed called RatNum or something that holds a numerator and a denominator int, and you use those for the calculations.
Thanks for the tip
you mean class for every method(+-*/) ? why?
is it possible for you to make one calculator and post it so i can understand it better?
(Mar 16, 2015 07:31 AM)iponu Wrote: Cool I remember that was the first program I wrote to.. People keep saying try write it in gui. Me personally I would tell you to stay away from it a bit, until you learn more about java classes, interfaces, arrays, arraylists, etc... Otherwise you will be tempted use a program that makes the gui for you rather than actually learning how to code it without a visual.
Thanks, i have actually done Core & Adv Java in college and in institution but still i was not able to code anything before 1 week ago.
I just need to learn once again.
* - Leostraza - Mar 17, 2015
Quote:you mean class for every method(+-*/) ? why?
This is what he means:
Code
public int add(int a, int b) { return a + b; }If you have a gui, there isn't a need for Switch/case just create buttonhandlers for each button, inside those handlers do the method. (add(1, 2), etc.)
Code
public class Calculator extends JFrame {
public Calculator() {
setTitle("Calculator");
//... blah blah blah
addButton.addEventListener(new AddButtonHandler());
}
public static void main(String[] args) {
new Calculator();
}
private class AddButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent e) {
textField.setText(Integer.toString(add(number1, number2)));
}
}
}Was bored, you could do something like that..
Maybe add the number to a stack (on the textField) which has a list of operations?