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Views: 1556 | Replies: 3 | Solved
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Join Date: Feb 2007
Posts: 3
Reputation: 
Rep Power: 0
Solved Threads: 0
Newbie Poster
the errors are commented in the code:
help???
help???
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import javax.swing.*;
import java.lang.*;
public class Kol2_1 extends Applet implements ActionListener
{
Button plus = new Button("+");
Button minus = new Button("-");
Button times = new Button("*");
Button div = new Button("/");
Button eq = new Button("=");
TextField pole = new TextField("E hej zver");
double x=0.0,y=0.0, z;
public void init()
{
try{
x=Double.parseDouble(JOptionPane.showInputDialog("Vnesete vrednost za x:"));
y=Double.parseDouble(JOptionPane.showInputDialog("Vnesete vrednost za y:"));
}
catch(StringIndexOutOfBoundsException n)
{JOptionPane.showMessageDialog(this, "Vnesete broj.");}
setLayout(new GridLayout(4,2));
add(plus);
add(minus);
add(times);
add(div);
add(eq);
add(pole);
plus.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/
minus.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/
times.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/
div.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/
eq.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/
}
public void actionPerformed(ActionEvent e)
{
switch(e.getSource()){ //incompatible types
case plus: { z=x+y;}
case minus: { z=x-y;}
case times: { z=x*y;}
case div: { try{z=x/y;}
catch(NumberFormatException m)
{
if(y==0) JOptionPane.showMessageDialog(this,"Division by zero.");
}
}
case eq: {pole.setText(""+z);}
}
}
} Last edited by PennyBoki : Feb 12th, 2007 at 6:42 pm.
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Join Date: Nov 2005
Posts: 72
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Solved Threads: 5
Junior Poster in Training
*squints at code*
.....
Haha, silly me. I missed this at first glance.
1) instead of
2)
Might wanna reconsider, with casting and/or an if-else statement.
.....
Haha, silly me. I missed this at first glance.
1) instead of
*.addActionPerformed(this); use *.addActionListener(this);2)
e.getSource() returns an Object, and switch statements work with int values. Might wanna reconsider, with casting and/or an if-else statement. synchronized (theWorld) { System.out.println ("It's all mine..."); }
How many people have code in their Sigs?
How many people have code in their Sigs?
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Join Date: Feb 2007
Posts: 3
Reputation:
Rep Power: 0
Solved Threads: 1
Newbie Poster
you are giving plus.addactionPerformed(this);. you should not give like that. please give plus.addActionListener(this);. and then after finishing the constructor write the method
public void actionPerformed(ActionEvent e)
{
String s=e.getActionCommand();
if(s.equals("+"))
{....}
}
here e.getActionCommand() method return the caption(that is the string that you written on the button). and then check whether it it equal to +,-,*,/ and then perform the relevant action.
public void actionPerformed(ActionEvent e)
{
String s=e.getActionCommand();
if(s.equals("+"))
{....}
}
here e.getActionCommand() method return the caption(that is the string that you written on the button). and then check whether it it equal to +,-,*,/ and then perform the relevant action.
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Originally Posted by PennyBoki 
the errors are commented in the code:
help???
import java.awt.*; import java.awt.event.*; import java.applet.*; import javax.swing.*; import java.lang.*; public class Kol2_1 extends Applet implements ActionListener { Button plus = new Button("+"); Button minus = new Button("-"); Button times = new Button("*"); Button div = new Button("/"); Button eq = new Button("="); TextField pole = new TextField("E hej zver"); double x=0.0,y=0.0, z; public void init() { try{ x=Double.parseDouble(JOptionPane.showInputDialog("Vnesete vrednost za x:")); y=Double.parseDouble(JOptionPane.showInputDialog("Vnesete vrednost za y:")); } catch(StringIndexOutOfBoundsException n) {JOptionPane.showMessageDialog(this, "Vnesete broj.");} setLayout(new GridLayout(4,2)); add(plus); add(minus); add(times); add(div); add(eq); add(pole); plus.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/ minus.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/ times.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/ div.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/ eq.addActionPerformed(this); /*cannot find symbol method addActionPerformed(Kol2_1)*/ } public void actionPerformed(ActionEvent e) { switch(e.getSource()){ //incompatible types case plus: { z=x+y;} case minus: { z=x-y;} case times: { z=x*y;} case div: { try{z=x/y;} catch(NumberFormatException m) { if(y==0) JOptionPane.showMessageDialog(this,"Division by zero."); } } case eq: {pole.setText(""+z);} } } }
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