:roll:Olá pessoal! alguém poderia explicar o código dessa calculadora feito em java? o que foi usado é para que? ? vlew :arrow:
calculator.java
import java.awt.<em>;
import java.lang.</em>;
import java.awt.event.<em>;
import java.applet.Applet;
import java.awt.datatransfer.</em>;
public class calculator extends Applet
{
public void init()
{
calf calWindow = new calf(“Java Calculator”);
calWindow.setSize(200, 250);
calWindow.setVisible(true);
calWindow.setResizable(false);
}
}
class calf extends Frame implements WindowListener, ActionListener, KeyListener
{
String command, copy, arg, chg, txt;
double result;
String number = “123456789.0”;
String operator = “/*-+=”;
CopyPaste cp;
Menu Menu1;
MenuBar Menubar1;
MenuItem menuitem1, menuitem2, menuitem3;
TextField entrytext;
Button numbut []; //Number buttons
Button combut []; //Command buttons
Panel companel, numpanel;
public static void main(String[] arguments)
{
calf calWindow = new calf(“Java Calculator”);
calWindow.setSize(200, 250);
calWindow.setVisible(true);
}
public calf(String title)
{
super(title);
addWindowListener(this);
addKeyListener(this);
cp = new CopyPaste();
//cp.clip = getToolkit().getSystemClipboard();
setBackground(Color.blue);
setLayout(new GridLayout(1, 1));
Menubar1 = new MenuBar();
Menu1 = new Menu(“Edit”);
menuitem1 = new MenuItem("&Copy");
Menu1.add(menuitem1);
menuitem1.addActionListener(this);
menuitem2 = new MenuItem("&Paste");
Menu1.add(menuitem2);
menuitem2.addActionListener(this);
menuitem3 = new MenuItem("&Exit");
Menu1.add(menuitem3);
menuitem3.addActionListener(this);
Menubar1.add(Menu1);
setMenuBar(Menubar1);
GridBagLayout gridbag = new GridBagLayout();
GridBagConstraints constraints = new GridBagConstraints();
setLayout(gridbag);
constraints.weighty = 1;
constraints.weightx = 1;
<a href="//constraints.fill">//constraints.fill</a> = GridBagConstraints.BOTH;
Font bigFont = new Font(“Courier”,Font.BOLD, 14);
entrytext = new TextField(20);
constraints.gridwidth = GridBagConstraints.REMAINDER;
gridbag.setConstraints(entrytext,constraints);
add(entrytext);
entrytext.setFont(bigFont);
entrytext.setEditable(false);
entrytext.setForeground(Color.black);
entrytext.setBackground(Color.white);
entrytext.addKeyListener(this);
entrytext.requestFocus();
constraints.weighty = 1;
constraints.weightx = 1;
companel = new Panel();
constraints.gridwidth = GridBagConstraints.REMAINDER;
gridbag.setConstraints(companel,constraints);
/*
Command GridLayout
| Back | CE | C |
*/
companel.setLayout();new GridLayout(1,3,5,5)
// Create the buttons
Font comsFont = new Font(“Arial”,Font.BOLD, 12);
String[] coms = { “Back”,“CE”,“C”
};
combut = new Button[3];
for (int i=0; i<=2; i++)
{
combut[i] = new Button(coms[i]);
companel.add(combut[i]);
combut[i].addActionListener(this);
combut[i].setFont(comsFont);
combut[i].addKeyListener(this);
}
add(companel);
companel.addKeyListener(this);
constraints.weighty = 4;
constraints.weightx = 1;
numpanel = new Panel();
constraints.gridwidth = GridBagConstraints.REMAINDER;
gridbag.setConstraints(numpanel,constraints);
/*
Number GridLayout
| 7 | 8 | 9 | / |sqr|
| 4 | 5 | 6 | * | % |
| 1 | 2 | 3 | - |1/x|
| 0 |+/-| . | + | = |
<em>/
numpanel.setLayout(new GridLayout(4,5,3,3));
// Create the buttons
String[] nums = { “7”,“8”,“9”,"/",“sqrt”,
“4”,“5”,“6”,"</em>","%",
“1”,“2”,“3”,"-",“1/x”,
“0”,"+/-",".","+","="
};
numbut = new Button[20];
for (int i=0; i<=19; i++)
{
numbut[i] = new Button(nums[i]);
numpanel.add(numbut[i]);
numbut[i].addActionListener(this);
numbut[i].addKeyListener(this);
if(operator.indexOf(nums[i]) > -1)
{
numbut[i].setForeground(Color.red);
}
else
{
numbut[i].setForeground(Color.blue);
}
}
add(numpanel);
numpanel.addKeyListener(this);
//initialize global variables.
command = “+”;
copy = “”;
chg = “N”;
txt = “”;
arg = “”;
result = 0;
}
public void actionPerformed(ActionEvent e)
{
if (e.getActionCommand() == “&Exit”)
{
setVisible(false);
System.exit(0);
}
else if (e.getActionCommand() == “&Copy”)
{
String txt = entrytext.getText();
if (txt != null)
{
cp.doCopy(txt);
}
}
else if (e.getActionCommand() == “&Paste”)
{
cp.doPaste();
if (cp.ctxt != null)
{
entrytext.setText(cp.ctxt);
}
}
else if (e.getActionCommand() == “Back”) back_space();
else if (e.getActionCommand() == “CE”) entrytext.setText("");
else if (e.getActionCommand() == “C”)
{
result = 0;
command = “+”;
entrytext.setText("");
}
else
{
arg = e.getActionCommand();
txt = entrytext.getText();
if(number.indexOf(arg) > -1)
{
if (chg == “Y”) txt = “”;
txt = txt + arg;
entrytext.setText(txt);
chg = “N”;
}
else check_entry();
}
}
public void keyPressed(KeyEvent k){}
public void keyReleased(KeyEvent k)
{
int ikey = k.getKeyCode();
if (ikey == 127) entrytext.setText("");
}
public void keyTyped(KeyEvent k)
{
int ikey = k.getKeyChar();
if (ikey == 8) back_space();
else if (ikey == 10)
{
arg = “=”;
txt = entrytext.getText();
display_ans();
}
else
{
txt = entrytext.getText();
char ckey = (char) ikey;
arg = String.valueOf(ckey);
if(number.indexOf(arg) > -1)
{
if (chg == “Y”) txt = “”;
txt = txt + arg;
entrytext.setText(txt);
chg = “N”;
}
else check_entry();
}
}
public void back_space()
{
txt = entrytext.getText();
int l = txt.length();
if (l > 0)
{
txt = txt.substring(0,l-1);
entrytext.setText(txt);
}
}
public void display_ans()
{
entrytext.setText(compute_tot(txt,command));
chg = “Y”;
command = “+”;
result = 0;
}
public void check_entry()
{
if(arg.equals("=")) display_ans();
else if(arg.equals("%"))
{
entrytext.setText(compute_tot(txt,arg));
chg = “Y”;
}
else if(operator.indexOf(arg) > -1)
{
entrytext.setText(compute_tot(txt,command));
command = arg;
chg = “Y”;
}
else if(arg == “sqrt”)
{
entrytext.setText(compute_tot(txt,arg));
chg = “Y”;
command = “”;
}
else if(arg == “+/-”)
{
Double tnum = Double.valueOf(txt);
double num = tnum.doubleValue();
num = num * -1;
entrytext.setText(String.valueOf(num));
chg = “Y”;
}
else if(arg == “1/x”)
{
entrytext.setText(compute_tot(txt,arg));
chg = “Y”;
}
}
String compute_tot(String t, String c)
{
Double tnum = Double.valueOf(t);
double num = tnum.doubleValue();
if (c.equals("+")) result = result + num;
else if (c.equals("-")) result = result - num;
else if (c.equals("*")) result = result * num;
else if (c.equals("/")) result = result / num;
else if (c.equals("%")) result = num / 100;
else if (c.equals("+/-")) result = num * -1;
else if (c.equals(“1/x”)) result = 1.000 / num;
else if (c.equals(“sqrt”)) result = Math.sqrt(num);
return String.valueOf(result);
}
public void windowClosing(WindowEvent we)
{
setVisible(false);
System.exit(0);
}
public void windowClosed(WindowEvent we) {}
public void windowDeiconified(WindowEvent we) {}
public void windowIconified(WindowEvent we) {}
public void windowOpened(WindowEvent we) {}
public void windowActivated(WindowEvent we) {}
public void windowDeactivated(WindowEvent we) {}
}
class CopyPaste implements ClipboardOwner
{
Clipboard clip;
String ctxt;
CopyPaste()
{
clip = new Clipboard(“clip”);
ctxt = null;
}
void doCopy(String txt)
{
StringSelection trans = new StringSelection(txt);
clip.setContents(trans, this);
}
void doPaste()
{
ctxt = null;
Transferable toPaste = clip.getContents(this);
if (toPaste != null)
{
try
{
ctxt = (String)toPaste.getTransferData(
DataFlavor.stringFlavor);
}
catch (Exception e)
{
System.out.println("Error – " + e.toString());
}
}
}
public void lostOwnership(Clipboard clip,
Transferable contents) {
}
}
