Java calculator source program

Import java. AWT .*;
Import javax. Swing .*;
Import java. AWT. event .*;
Class calculation extends jframe
{Public calculation ()/* constructor */
{Super ("counter ");
This. setdefaclocloseoperation (jframe. exit_on_close );
Inittextpanel ();/* text box */
Initcontrolpanel ();/* control key */
Initkeypanel ();/* Numbers and operators */
Container pane = getcontentpane ();
Pane. setlayout (New borderlayout ());
Pane. Add (textpanel, borderlayout. North );
Pane. Add (controlpanel, borderlayout. center );
Pane. Add (keypanel, borderlayout. South );
Pack ();
Try
{Uimanager. setlookandfeel ("com. Sun. java. Swing. plaf. Windows. windowslookandfeel ");
}
Catch (exception ex)
{;}/* Set the view of windons */
Swingutilities. updatecomponenttreeui (this );
Setresizable (false );
Setvisible (true );
}

Private void inittextpanel ()/* set text box */
{Textpanel = new jpanel ();
Textpanel. setlayout (New flowlayout ());
Resultarea = new jtextfield ("0", 25 );
Resultarea. seteditable (false);/* set to uneditable */
Color color = color. White;
Resultarea. setbackground (color);/* color */
Resultarea. sethorizontalalignment (jtextfield. Right);/* set the display position */
Textpanel. Add (resultarea );
}

Private void initcontrolpanel ()/* set the control key */
{Controlpanel = new jpanel ();
Controlpanel. setlayout (New gridlayout (1, 3, 4 ));
Jbutton b1 = new jbutton ("backspace");/* backspace key */
B1.setfont (font1 );
B1.addactionlistener (New actionlistener ()
{Public void actionreceivmed (actionevent E)
{String S1 = resultarea. gettext ();
Int L = s1.length ();
Resultarea. settext (s1.substring (0 L-1 ));
}
});

Controlpanel. Add (B1 );
Jbutton b2 = new jbutton ("CE");/* ce key */
B2.setfont (font1 );
B2.addactionlistener (New actionlistener ()
{Public void actionreceivmed (actionevent E)
{Resultarea. settext ("0 ");
Isnew = true;
}
});
Controlpanel. Add (B2 );

Jbutton B3 = new jbutton ("C");/* C key */
B3.setfont (font1 );
B3.addactionlistener (New actionlistener ()
{Public void actionreceivmed (actionevent E)
{Resultarea. settext ("0 ");
Pnum = "";
Operation = "";
Isnew = true;
}
});
Controlpanel. Add (B3 );
}

Private void initkeypanel ()/* set the number key and operator key */
{String key [] = {"7", "8", "9", "/", "SQRT", "4", "5", "6 ", "*", "%", "1", "2", "3", "-", "1/X", "0", "+ /-", ". "," + "," = "};

Keypanel = new jpanel ();
Keypanel. setlayout (New gridlayout (4,5, 4,4 ));
For (INT I = 0; I <20; I ++)
{String label = Key [I];
Jbutton B = new jbutton (Label );
B. setactioncommand (Key [I]);
B. setfont (font2 );
Keypanel. Add (B );
B. addactionlistener (New actionlistener ()/* anonymous listener */
{Public void actionreceivmed (actionevent E)
{Key_actionreceivmed (E );
}
});
}
}
Public void key_actionreceivmed (actionevent E)/* number key and operator key anonymous listener */
{String S = (E. getactioncommand ());
String ST = resultarea. gettext ();
If (S. Equals ("0")/* The number of inputs is 0 */
{If (St. Equals ("0 "))
Return;
Else
{If (! Isnew)
Resultarea. settext (ST + "0 ");
Else
Resultarea. settext ("0 ");
}
Isnew = false;
Return;
}

If (S. Equals ("+/-")/* The number of inputs is + /-*/
{Double K = double. parsedouble (ST );
{If (K! = 0)
Display (-k );

}
Return;
}

If (S. equals ("1") | S. equals ("2") | S. equals ("3") | S. equals ("4") | S. equals ("5") | S. equals ("6") | S. equals ("7") | S. equals ("8") | S. equals ("9")/* input 1-9 */

{If (! Isnew)
Resultarea. settext (ST + S );
Else
{Resultarea. settext (s );
Isnew = false;
}
Return;
}

If (S. Equals (".")/* enter the decimal point */
{If (resultarea. gettext (). indexof (".") =-1)/* No decimal point */
{If (isnew)
{Resultarea. settext ("0 .");
Isnew = false;
}
Else
Resultarea. settext (ST + ".");
}
Return;
}

Isnew = true;/* press the operator and enter a new number */
If (S. Equals ("= "))
{Compute (s );
Operation = "";
}
Else
{If (S. equals ("+") | S. equals ("-") | S. equals ("*") | S. equals ("/")/* binary operator number */

{If (operation. Equals (""))
{Pnum = resultarea. gettext ();
Operation = s;
}
Else
Compute (s );
}
Else/* maxcompute */
{Count count1 = new count (double. parsedouble (ST ));
If (S. Equals ("SQRT "))
{
Display (count1.sqrt ());

}
Else
{If (S. Equals ("1/X "))
{If (St. Equals ("0 "))
{Resultarea. settext ("the divisor cannot be 0 .");
Operation = "";
Pnum = "";
}
Else
Display (count1.reciprocal ();/* calculate the reciprocal */
}
Else
Display (double. parsedouble (ST)/100);/* enter % to divide the currently displayed value to 100 */

}
}
}
}

Private void compute (string S)
{If (S. Equals ("= "))
{If (operation. Equals (""))
Return;
}
Double data1 = double. parsedouble (pnum );
Double data2 = double. parsedouble (resultarea. gettext ());
Count count2 = new count (data1, data2);/* addition, subtraction, multiplication, division, and calculation */
If (operation. Equals ("+ "))
Display (count2.plus ()));
Else
{If (operation. Equals ("-"))
Display (count2.minus ()));
Else
{If (operation. Equals ("*"))
Display (count2.multiply ()));
Else
If (operation. Equals ("/"))
{If (data2 = 0)
{Resultarea. settext ("the divisor cannot be 0 ");
Operation = "";
Pnum = "";
Return;
}
Else
Display (count2.divide ()));
}
}
}
Operation = "";/* indicates the current character */
Pnum = resultarea. gettext ();/* The number of operations is the current number of texts */
}

Public void display (double result)/* display output method */
{Int A = (INT) result;
If (A = Result)
Resultarea. settext (string. valueof ());
Else
Resultarea. settext (string. valueof (result ));
If (resultarea. gettext (). Equals ("Nan "))
Resultarea. settext ("invalid input function ");
}

Private jpanel textpanel;/* textbox cotton panel */
Private jtextfield resultarea;/* text box */
Private jpanel controlpanel;/* control key Panel */
Private jpanel keypanel;/* number key and operator key Panel */
Private font font1 = new font ("dialog", 0, 10);/* Control Key font */
Private font font2 = new font ("dialog",);/* font of the number key and symbol key */
Private string pnum = "";/* first operand */
Private Boolean isnew = true;/* determines whether the number is new */
Private string operation = "";/* operator */
}


Class tester/* test class */
{
Public static void main (string [] ARGs)
{
New calculation ();
}
}