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Hey Experts,
Can anyone tell me which modifications can i do to the code below so not to look same as the original but to be the same effective ?????
Thanks in advance
Can anyone tell me which modifications can i do to the code below so not to look same as the original but to be the same effective ?????
Thanks in advance
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class Calculator extends Applet implements ActionListener
{
private TextField Panel;
private Button B0,
B1,
B2,
B3,
B4,
B5,
B6,
B7,
B8,
B9,
BDiv,
BMul,
BAdd,
BSub,
BResult,
B1p,
B2p,
BPoint,
BClear;
private int state, error;
public void init()
{
setBackground(Color.white);
setLayout(null);
//resize(500, 500);
state = 0;
error = 0;
Panel = new TextField();
Panel.setBounds( 20, 20, 165, 25);
add(Panel);
B0 = new Button("0");
B0.setBounds (20, 160, 25, 25);
add(B0);
B1 = new Button("1");
B1.setBounds (20, 125, 25, 25);
add(B1);
B2 = new Button("2");
B2.setBounds (55, 125, 25, 25);
add(B2);
B3 = new Button("3");
B3.setBounds (90, 125, 25, 25);
add(B3);
B4 = new Button("4");
B4.setBounds (20, 90, 25, 25);
add(B4);
B5 = new Button("5");
B5.setBounds (55, 90, 25, 25);
add(B5);
B6 = new Button("6");
B6.setBounds (90, 90, 25, 25);
add(B6);
B7 = new Button("7");
B7.setBounds (20, 55, 25, 25);
add(B7);
B8 = new Button("8");
B8.setBounds (55, 55, 25, 25);
add(B8);
B9 = new Button("9");
B9.setBounds (90, 55, 25, 25);
add(B9);
BDiv = new Button("/");
BDiv.setBounds (160, 90, 25, 25);
add(BDiv);
BMul = new Button("*");
BMul.setBounds (125, 90, 25, 25);
add(BMul);
BAdd = new Button("+");
BAdd.setBounds (125, 55, 25, 25);
add(BAdd);
BSub = new Button("-");
BSub.setBounds (160, 55, 25, 25);
add(BSub);
BResult = new Button("=");
BResult.setBounds (90, 160, 25, 25);
add(BResult);
B1p = new Button("(");
B1p.setBounds (125, 125, 25, 25);
add(B1p);
B2p = new Button(")");
B2p.setBounds (160, 125, 25, 25);
add(B2p);
BPoint = new Button(".");
BPoint.setBounds (55, 160, 25, 25);
add(BPoint);
BClear = new Button("Clear");
BClear.setBounds (115, 170, 70, 25);
add(BClear);
Panel.addActionListener(this);
B0.addActionListener(this);
B1.addActionListener(this);
B2.addActionListener(this);
B3.addActionListener(this);
B4.addActionListener(this);
B5.addActionListener(this);
B6.addActionListener(this);
B7.addActionListener(this);
B8.addActionListener(this);
B9.addActionListener(this);
BDiv.addActionListener(this);
BMul.addActionListener(this);
BAdd.addActionListener(this);
BSub.addActionListener(this);
BResult.addActionListener(this);
B1p.addActionListener(this);
B2p.addActionListener(this);
BPoint.addActionListener(this);
BClear.addActionListener(this);
}
/*
Method: paint
Purpose: Draw the outline of calculator *(this method can auto. draw when develop Applet, but it isn't Applet's method)
Parameters: Graphics
Returns: None
*/
public void paint(Graphics graphic)
{
graphic.setColor(Color.black);
graphic.fillRoundRect( 5, 5, 195, 200, 15, 15);
}
public void actionPerformed(ActionEvent event)
{
if (event.getSource() instanceof Button)
{
Button clickedButton = (Button) event.getSource();
if (clickedButton == BClear)
{
ClearPanel();
state = 0;
}
else if (clickedButton == BResult)
{
error = 0;
Compute();
state = 1;
}
else
{
if (state == 1)
{
ClearPanel(); //clear panel after calculation
state = 0;
}
DisplayEx(clickedButton);
}
}
else
{
error = 0;
Compute();
state = 1;
}
}
/*
Method: ClearPanel
Purpose: Clear Panel TextField objects
Parameters: None
Returns: None
*/
private void ClearPanel()
{
Panel.setText("");
}
/*
Method: DisplayEx
Purpose: Display the whole expression that the user enters
Parameters: clickedButton
Returns: None
*/
private void DisplayEx(Button ClickedButton)
{
String tmpstr;
tmpstr = Panel.getText();
if (ClickedButton == B0) Panel.setText(tmpstr+"0");
if (ClickedButton == B1) Panel.setText(tmpstr+"1");
if (ClickedButton == B2) Panel.setText(tmpstr+"2");
if (ClickedButton == B3) Panel.setText(tmpstr+"3");
if (ClickedButton == B4) Panel.setText(tmpstr+"4");
if (ClickedButton == B5) Panel.setText(tmpstr+"5");
if (ClickedButton == B6) Panel.setText(tmpstr+"6");
if (ClickedButton == B7) Panel.setText(tmpstr+"7");
if (ClickedButton == B8) Panel.setText(tmpstr+"8");
if (ClickedButton == B9) Panel.setText(tmpstr+"9");
if (ClickedButton == BDiv) Panel.setText(tmpstr+"/");
if (ClickedButton == BMul) Panel.setText(tmpstr+"*");
if (ClickedButton == BAdd) Panel.setText(tmpstr+"+");
if (ClickedButton == BSub) Panel.setText(tmpstr+"-");
if (ClickedButton == B1p)Panel.setText(tmpstr+"(");
if (ClickedButton == B2p)Panel.setText(tmpstr+")");
if(ClickedButton == BPoint)Panel.setText(tmpstr+".");
}
/*
Method: Compute
Purpose: Calculate the expression and shown the result, when the user hit return key or "=" button.
Parameters: The whole expression
Returns: None
*/
private void Compute()
{
String Tmpstr, Result="";
char ch;
int i, no_of_char,
no_of_par = 0;
Tmpstr = Panel.getText();
no_of_char = Tmpstr.length();
//Expression brief checking
for (i = 0; i < no_of_char; i++)
{
ch = Tmpstr.charAt(i);
if (ch == ')') no_of_par--;
if (no_of_par < 0) error = 1;
if (ch == '(') no_of_par++;
if (ch < '(' || ch > '9' || ch == ',') error = 2;
if (ch == '.' && (i+1 < Tmpstr.length()) )
for ( int j = i+1; (j < Tmpstr.length()) && ((Character.isDigit(Tmpstr.charAt(j))) || ((Tmpstr.charAt(j))) == '.'); j++ )
if (Tmpstr.charAt(j) == '.') error = 3;
//If an operand has more than one point return error
}//End of expression brief checking
if (no_of_par != 0) error = 1; //If open and close parentheses do not match return error
if (error != 0) Err_msg(error); //An error perform to prompt error message
else Result = Calculate(Tmpstr); //No error perform to calculate expression
if (error != 0) Err_msg(error); //An error perform to prompt error message
else Panel.setText(Result); //No error show result
}
/*
Method: Calculate
Purpose: Implement the expression
Parameters: Expression
Returns: None
*/
private String Calculate(String expression)
{
String result = expression, f_operand, r_operand;
char cha;
int index, f_index, r_index,
no_of_cha = result.length(),
no_of_pare = 0, pare_match = 0, op_index = 0, cp_index = 0;
if (error == 0)
{
//Checking Parentheses
for (index = 0; index < no_of_cha; index++)
{
cha = result.charAt(index);
if (cha == '(')
{
if (pare_match == 0) op_index = index;
pare_match ++;
no_of_pare ++;
}
if (cha == ')')
{
pare_match --;
if (pare_match == 0) cp_index = index;
}
}//End of checking Parentheses
if (op_index+1 == cp_index) error = 3;
//Recursive Calculate, when parentheses existed
if (error == 0 && no_of_pare > 0)
{
if ((op_index == 0) && (cp_index == (no_of_cha - 1)) && (op_index != cp_index)) result = Calculate(result.substring(op_index + 1, cp_index));
else if (op_index == 0 && cp_index > 0)
{
if ( (Character.isDigit(result.charAt(cp_index+1))) ) error = 3;
else
{
result = Calculate(result.substring(op_index + 1, cp_index)) + result.substring(cp_index + 1);
no_of_pare--;
while(no_of_pare != 0)
{
result = Calculate(result);
no_of_pare--;
}
}
}
else if ((op_index > 0) && (cp_index > 0) && (cp_index != no_of_cha -1))
{
if ( (Character.isDigit(result.charAt(cp_index+1))) || (Character.isDigit(result.charAt(op_index-1))) ) error = 3;
else
{
result = result.substring(0, op_index) + Calculate(result.substring(op_index +1, cp_index)) + result.substring(cp_index +1);
no_of_pare--;
while(no_of_pare != 0)
{
result = Calculate(result);
no_of_pare--;
}
}
}
else if (cp_index == no_of_cha -1 && op_index > 0)
{
if ( (Character.isDigit(result.charAt(op_index-1))) ) error = 3;
else
{
result = result.substring(0, op_index) + Calculate(result.substring(op_index + 1, cp_index));
no_of_pare--;
while(no_of_pare != 0)
{
result = Calculate(result);
no_of_pare--;
}
}
}
}//End of recursive Calculate statement
//Implement algorithm
if (no_of_pare == 0 && error == 0)
{
if ( (!(Character.isDigit(result.charAt(0))) && (result.charAt(0) != '-')) || !(Character.isDigit(result.charAt(result.length()-1))) ) error = 3;
//Implement multiply and divide first
for (index = 0; index < result.length() && (error == 0); index++)
{
cha = result.charAt(index);
if (cha == '*' || cha == '/')
{
if ( !(Character.isDigit(result.charAt(index-1))) || ( !(Character.isDigit(result.charAt(index+1))) && (result.charAt(index+1) != '-') ) ) error = 3;
if (result.charAt(index+1) == '-')
if ( !(Character.isDigit(result.charAt(index+2))) ) error = 3;
if (error == 0)
{
f_index = index - 1;
if (f_index > 2)
if ( ((result.charAt(f_index-1)) == '-') && ((result.charAt(f_index-2)) == 'E') )
f_index = f_index - 2;
while ( (f_index > 0) && ((Character.isDigit(result.charAt(f_index-1))) || ((result.charAt(f_index-1)) == '.') || ((result.charAt(f_index-1)) == 'E')) )
{
f_index--;
}
if (f_index ==1)
if ((result.charAt(f_index-1)) == '-')
f_index--;
if (f_index > 2)
if ( ((result.charAt(f_index-1)) == '-') && !(Character.isDigit(result.charAt(f_index-2))) )
f_index--;
f_operand = result.substring(f_index, index);
r_index = index + 1;
while ( (r_index < result.length()-1) && ((Character.isDigit(result.charAt(r_index+1))) || ((result.charAt(r_index+1)) == '.') || ((result.charAt(r_index+1)) == 'E')) )
{
r_index++;
if (r_index < result.length()-2)
if ( ((result.charAt(r_index)) == 'E') && ((result.charAt(r_index+1)) == '-') )
r_index++;
}
r_operand = result.substring(index+1, r_index+1);
if ( (f_index != 0) && (r_index != result.length()-1) )
{
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'N') error = 4; //If an answer is not a number return error
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'I') error = 5; //If an answer is Infinity return error
result = result.substring(0, f_index) + Algorithm(cha, f_operand, r_operand) + result.substring(r_index+1);
index = 0;
}
else if ( (f_index == 0) && (r_index == result.length()-1) )
{
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'N') error = 4; //If an answer is not a number return error
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'I') error = 5; //If an answer is Infinity return error
result = Algorithm(cha, f_operand, r_operand);
}
else if (f_index == 0)
{
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'N') error = 4; //If an answer is not a number return error
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'I') error = 5; //If an answer is Infinity return error
result = Algorithm(cha, f_operand, r_operand) + result.substring(r_index+1);
index = 0;
}
else if (r_index == result.length()-1)
{
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'N') error = 4; //If an answer is not a number return error
if (Algorithm(cha, f_operand, r_operand).charAt(0) == 'I') error = 5; //If an answer is Infinity return error
result = result.substring(0, f_index) + Algorithm(cha, f_operand, r_operand);
}
}
}
}//End of implement multiply and divide
//Implement add and subtract
for (index = 0; index < result.length() && (error == 0); index++)
{
if (index == 0 && result.charAt(index) == '-') index = 1;
if (index > 0)
if ( ((result.charAt(index)) == 'E') && ((result.charAt(index+1)) == '-') )
index = index + 2;
cha = result.charAt(index);
if (cha == '+' || cha == '-')
{
if ( !(Character.isDigit(result.charAt(index-1))) || ( !(Character.isDigit(result.charAt(index+1))) && (result.charAt(index+1) != '-') ) ) error = 3;
if (result.charAt(index+1) == '-')
if ( !(Character.isDigit(result.charAt(index+2))) ) error = 3;
if (error == 0)
{
f_index = 0;
f_operand = result.substring(f_index, index);
r_index = index + 1;
while ( (r_index < result.length()-1) && ((Character.isDigit(result.charAt(r_index+1))) || ((result.charAt(r_index+1)) == '.') || ((result.charAt(r_index+1)) == 'E')) )
{
r_index++;
if (r_index < result.length()-2)
if ( ((result.charAt(r_index)) == 'E') && ((result.charAt(r_index+1)) == '-') )
r_index++;
}
r_operand = result.substring(index+1, r_index+1);
result = Algorithm(cha, f_operand, r_operand) + result.substring(r_index+1);
index = 0;
}
}
}//End of implement add and subtract
}//End of implement algorithm
}
return result;
}
/*
Method: Algorithm
Purpose: Implement the simple expression
Parameters: Operator, front value and rear value
Returns: None
*/
private String Algorithm(char Operator, String F_operand, String R_operand)
{
Double F, R;
double f, r,
ans = 0;
String res;
F = new Double(F_operand);
R = new Double(R_operand);
f = F.doubleValue();
r = R.doubleValue();
if (Operator == '+') ans = f + r;
if (Operator == '-') ans = f - r;
if (Operator == '*') ans = f * r;
if (Operator == '/') ans = f / r;
res = Double.toString(ans);
return res;
}
/*
Method: Err_msg
Purpose: Prompt error message
Parameters: Error level
Returns: None
*/
private void Err_msg(int error)
{
switch(error)
{
case 1:
Panel.setText("Parentheses do not match");
break;
case 2:
Panel.setText("Invalid input");
break;
case 3:
Panel.setText("Invalid expression");
break;
case 4:
Panel.setText("Not a number exist");
break;
case 5:
Panel.setText("Infinity exist");
break;
default:
Panel.setText("Unknow error");
break;
}
}
}
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krakatoa
Bit of homework workaround?
Homework? Where do they teach you how to ..........................
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