char a = s.charAt(i);  text.setText(text.getText() + a);  }  }  if (temp==ce)  {   text.setText("0.");   clear=true;   first=1;  }  if (temp==c)  {   text.setText("0.");   ;   clear=true;   first=1;  }  if(temp==num0)   {    if(clear==false)//判斷是否點(diǎn)擊了符號(hào)位    text.setText("");    text.setText(text.getText()+"0");   }  if(temp==num1)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"1");    clear=true;//第二次不在清空（前二句）   }  if(temp==num2)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"2");    clear=true;   }  if(temp==num3)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"3");    clear=true;   }  if(temp==num4)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"4");    clear=true;   }  if(temp==num5)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"5");    clear=true;   }  if(temp==num6)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"6");    clear=true;   }  if(temp==num7)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"7");    clear=true;   }  if(temp==num8)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"8");    clear=true;   }  if(temp==num9)   {    if(clear==false)    text.setText("");    text.setText(text.getText()+"9");    clear=true;   }   if(temp==aa)   {    text.setText(text.getText()+"A");   }  if(temp==bb)   {    text.setText(text.getText()+"B");   }  if(temp==cc)   {    text.setText(text.getText()+"C");   }  if(temp==dd)   {    text.setText(text.getText()+"D");   }  if(temp==ee)   {    text.setText(text.getText()+"E");   }  if(temp==ff)   {    text.setText(text.getText()+"F");   }   if(temp==dian)   {    clickable=true;    for (int i = 0; i < text.getText().length(); i++)   if ('.' == text.getText().charAt(i))   {   clickable=false;   break;   } //第一層判斷是否里面含有小數(shù)點(diǎn);    if(clickable==true)//第二壇判斷    text.setText(text.getText()+".");   }  try  {   if(temp==jia)   {//加法    qian=Double.parseDouble(text.getText());    fuhao="+";    clear=false;   }   if(temp==jian)   {    qian=Double.parseDouble(text.getText());    fuhao="-";    clear=false;    ;   }   if(temp==cheng)   {    qian=Double.parseDouble(text.getText());    fuhao="*";    clear=false;   }   if(temp==chu)   {    qian=Double.parseDouble(text.getText());    fuhao="/";    clear=false;   }   if(temp==deng)   {    double ss=Double.parseDouble(text.getText());    text.setText("");    if(fuhao=="+")    text.setText(qian+ss+"");    if(fuhao=="-")    text.setText(qian-ss+"");    if(fuhao=="*")    text.setText(qian*ss+"");    if(fuhao=="/")    text.setText(qian/ss+"");    clear=false;//要清空前一次的數(shù)據(jù)    ;   }   if(temp==kai)   {  String s = text.getText();  if (s.charAt(0) == '-')  {   text.setText("負(fù)數(shù)不能開根號(hào)");  }  else  text.setText(Double.toString(java.lang.Math.sqrt(Double.parseDouble(text.getText()))));  clear=false;  }  if(temp==diao)  {   if (text.getText().charAt(0) == '0'&&text.getText().length() == 1)    {    text.setText("除數(shù)不能為零");    }  else  {  boolean isDec = true;   int i, j, k;   String s = Double.toString(1 / Double.parseDouble(text.getText()));   for (i = 0; i < s.length(); i++)   if (s.charAt(i) == '.')   break;   for (j = i + 1; j < s.length(); j++)   if (s.charAt(j) != '0')   {   isDec = false;   break;   }   if (isDec == true)   {   String stemp = "";   for (k = 0; k < i; k++)    stemp += s.charAt(k);    text.setText(stemp);   }   else   text.setText(s);   }    clear=false;  }  if(temp==qiuyi)  {   text.setText("0");   clear=false;  }  if (temp == fu)  { //導(dǎo)師，此方法參考書中例子   boolean isNumber = true;   String s = text.getText();   for (int i = 0; i < s.length(); i++)   if (! (s.charAt(i) >= '0' && s.charAt(i) <= '9' || s.charAt(i) == '.' ||   s.charAt(i) == '-'))        {     isNumber = false;     break;     }   if (isNumber == true)    {   //如果當(dāng)前字符串首字母有'-'號(hào),代表現(xiàn)在是個(gè)負(fù)數(shù),再按下時(shí),則將首符號(hào)去掉     if (s.charAt(0) == '-')     {     text.setText("");     for (int i = 1; i < s.length(); i++)         {       char a = s.charAt(i);       text.setText(text.getText() + a);           }     }      //如果當(dāng)前字符串第一個(gè)字符不是符號(hào)，則添加一個(gè)符號(hào)在首字母處   else   text.setText('-' + s);   }  } } catch(Exception eee) {  System.out.println("運(yùn)算時(shí),首先輸入數(shù)字或字符");  text.setText("運(yùn)算出錯(cuò)");  clear=false; } } class WindowDestroyer extends WindowAdapter {//退出窗口動(dòng)作  public void windowClosing(WindowEvent e)  {  System.exit(0);  } }class objConversion{//導(dǎo)師,本進(jìn)制類參考了CSMD類轉(zhuǎn)換例子 public void objConversion () { } public String decDec (int decNum) {//10  String strDecNum = Integer.toString(decNum);  for (int i = strDecNum.length(); i < 3; i++)  {   strDecNum = "0" + strDecNum;  } // return strDecNum;  return invert (strDecNum, 5); } public String decHex (int decNum) {//10 to 16  String strHexNum = "";  int currentNum = 0;  while (decNum != 0)  {   if (decNum > 15)   {    currentNum = decNum % 16;    decNum /= 16;   }   else   {    currentNum = decNum;    decNum = 0;   }   switch (currentNum)   {    case 15: strHexNum += "F";       break;    case 14: strHexNum += "E";       break;    case 13: strHexNum += "D";       break;    case 12: strHexNum += "C";       break;    case 11: strHexNum += "B";       break;    case 10: strHexNum += "A";       break;    default: strHexNum += Integer.toString(currentNum);       break;   }  }  return invert (strHexNum, 2); } public String decOct (int decNum) {//10 to 8  String strOctNum = "";  while (decNum != 0)  {   if (decNum > 7)   {    strOctNum += Integer.toString(decNum % 8);    decNum /= 8;   }   else   {    strOctNum += Integer.toString(decNum);    decNum = 0;   }  }  return invert (strOctNum, 3); } public String decBin (int decNum) {//10 to 2  String strBinNum = "";  while (decNum != 0)  {   if (decNum > 1)   {    strBinNum += Integer.toString(decNum % 2);    decNum /= 2;   }   else   {    strBinNum += Integer.toString(decNum);    decNum = 0;   }  }  return invert (strBinNum, 8); } private String invert (String strNum, int minLength) //轉(zhuǎn)換長(zhǎng)度 {  String answer = "";  int length = strNum.length();  if (length < minLength)  {   for (int padding = (minLength - length); padding > 0; padding--)   {    answer += "0";   }  }  for (int i = length; i > 0; i--)  {   answer += strNum.charAt (i - 1);  }  return answer; }} public static void main(String arg[])//產(chǎn)生窗口 {  PrefectCalculator win = new PrefectCalculator();  win.setVisible(true); }}