calculator.java

⑴定义组件：0~9,+、-、*、/、sqrt()、1/x、％、C=按钮；显示屏文本行；菜单； ⑵要求能关闭窗口；点击按钮

            prekey=-1;
            if(Double.parseDouble(textAnswer.getText())==0){
              textAnswer.setText("除数不能为零");
              clickable=false;
            }
            else{
              answerd/=Double.parseDouble(textAnswer.getText());
              textAnswer.setText(df.format(answerd));
            }
          }
        }
        prekey=5;
      }
      //'%'操作，对第二个操作数除以100
      if (temp == buttonMod && clickable == true) {
        if (answerd == 0) {
          String s = textAnswer.getText();
          textAnswer.setText(s);
        }
        else {
          boolean isDot = false;
          for (int i = 0; i < textAnswer.getText().length(); i++)
            if ('.' == textAnswer.getText().charAt(i)) {
              isDot = true;
              break;
            }
          //如果是double数，除100
          if (isDot == true) {
            double dtemp = Double.parseDouble(textAnswer.getText());
            dtemp = dtemp / 100.0;
            textAnswer.setText(Double.toString(dtemp));
          }
          else {
            //如果是int数但能被100整除，则去掉末尾两个零
            if (Integer.parseInt(textAnswer.getText()) % 100 == 0) {
              int itemp = Integer.parseInt(textAnswer.getText());
              itemp /= 100;
              textAnswer.setText(Integer.toString(itemp));
            }
            //如果是int数，但不能被100整除，则按double数处理
            else {
              double dtemp = Double.parseDouble(textAnswer.getText());
              dtemp = dtemp / 100.0;
              textAnswer.setText(Double.toString(dtemp));
            }
          }
        }
      }
      //开根号运算
      if (temp == buttonSqrt && clickable == true) {
        String s = textAnswer.getText();
        if (s.charAt(0) == '-') {
          textAnswer.setText("负数不能开根号");
          clickable = false;
        }
        else
          textAnswer.setText(Double.toString(java.lang.Math.sqrt(Double.
              parseDouble(textAnswer.getText()))));
      }
      //倒数运算
      if (temp == buttonDao && clickable == true) {
        if (textAnswer.getText().charAt(0) == '0' &&
            textAnswer.getText().length() == 1) {
          textAnswer.setText("零不能求倒数");
          clickable = false;
        }
        else {

              String s = Double.toString(1 / Double.parseDouble(textAnswer.getText()));
              textAnswer.setText(s);
        }
      }
      //sin运算
      if (temp == buttonsin && clickable == true ) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.sin(x);
      	textAnswer.setText(""+result);
      }
      //cos运算
      if (temp == buttoncos && clickable == true) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.cos(x);
      	textAnswer.setText(""+result);
      }
      //tan运算
      if (temp == buttontan && clickable == true) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.tan(x);
      	textAnswer.setText(""+result);
      }
      //asin运算
      if (temp == buttonasin && clickable == true) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.asin(x);
      	textAnswer.setText(""+result);
      }
      //acos运算
      if (temp == buttonacos && clickable == true) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.acos(x);
      	textAnswer.setText(""+result);
      }
      //atan运算
      if (temp == buttonatan && clickable == true) 
      {
      	double x;
      	if(cb==false) x=Double.parseDouble(textAnswer.getText());
      	else x=Double.parseDouble(textAnswer.getText())*Math.PI/180;
      	double result =Math.atan(x);
      	textAnswer.setText(""+result);
      }
      //abs运算
      if (temp == buttonabs && clickable == true) 
      {
      	double result =Math.abs(Double.parseDouble(textAnswer.getText()));
      	textAnswer.setText(""+result);
      }
      //n!运算
      if (temp == buttonn && clickable == true) 
      {
      	double result =Double.parseDouble(textAnswer.getText());
      	int k=(int)result-1;
      	for(int i=k;i>=1;i--) result*=i;
      	textAnswer.setText(df.format(result));
      }
      //log运算 以e为底
      if (temp == buttonlog && clickable == true) 
      {
      	double result =Math.log(Double.parseDouble(textAnswer.getText()));
      	textAnswer.setText(""+result);
      }
      //x的立方
      if (temp == buttonx3 && clickable == true) 
      {
      	double x=Double.parseDouble(textAnswer.getText());
      	double result =x*x*x;
      	textAnswer.setText(""+result);
      }
      //x的平方根
      if (temp == buttonx && clickable == true) 
      {
      	double result =Math.sqrt(Double.parseDouble(textAnswer.getText()));
      	textAnswer.setText(""+result);
      } 
      //按下'+/-'按钮时处理
      if (temp == buttonAddAndSub && clickable == true) {
        String s = textAnswer.getText();
        double result=Double.parseDouble(s);
          if (s.charAt(0) == '-') 
            {result=Math.abs(result);
            textAnswer.setText(""+result);}
          else
            textAnswer.setText('-' + s);
      }
      //计算器有关内存操作
      //'MC'的操作，将内存清0
      if (temp == buttonMC && clickable == true) {
        memoryd=0;
        textMemory.setText("");
      }
      //'MS'的操作，将当前文本框内容保存入内存，显示'M'
      if (temp == buttonMS && clickable == true) {
          textMemory.setText("   M");
          memoryd = Double.parseDouble(textAnswer.getText());
      }
      //'MR'的操作，将存储器中的信息输出
      if (temp == buttonMR && clickable == true) {
        if (memoryd != 0)
          textAnswer.setText(Double.toString(memoryd));
      }
      //'M+'的功能，将当前文本框里的数据和存储器中数据相加后，再存入存储器
      if (temp == buttonMAdd && clickable == true)
          memoryd += Double.parseDouble(textAnswer.getText());
      //按下'Backspace'键，利用循环将当前字符串中的最后一个字母删除
      if (temp == buttonBk && clickable == true) {
        String s = textAnswer.getText();
        textAnswer.setText("");
        for (int i = 0; i < s.length() - 1; i++) {
          char a = s.charAt(i);
          textAnswer.setText(textAnswer.getText() + a);
        }
      }
      //按下'CE'按钮，将当前文本框内数据清除
      if (temp == buttonCe) {
        textAnswer.setText("");
        clickable = true;
      }
      //按下'C'按钮，文本框内数据清除，同时var,answer清0
      if (temp == buttonC) {
        vard = answerd = 0;
        textAnswer.setText("");
        clickable = true;
      }
      
    }
    //输入中如果有操作非法，比如按下两次'+'，捕获异常
    catch (Exception e) {
      textAnswer.setText("操作非法");
      clickable = false;
    }
  }
  private class MenuBAction implements ActionListener 
		{
			public void actionPerformed(ActionEvent event) {
		Object lastcommand = event.getSource();
		try
		{
			//按下'复制'菜单栏
           if (lastcommand == copyItem) 
              copy = textAnswer.getText();
          //按下'粘贴'菜单栏
          if (lastcommand == pasteItem) 
             textAnswer.setText(copy);
          if (lastcommand == sItem) 
            JOptionPane.showMessageDialog(panel, "当前是标准型计算器，\n科学型计算器有待更新。");
          //按下'帮助主题'菜单栏
          if (lastcommand == topHelp) 
            JOptionPane.showMessageDialog(panel, scrollHelp);
         //按下'数字分组'菜单栏
          if (lastcommand == numberGroup) {
             if (numberGroup.getText().compareTo("   数字分组(I)") == 0)
                 numberGroup.setText("√数字分组(I)");
              else
                numberGroup.setText("   数字分组(I)");
             }
       //按下'关于'菜单栏
      if (lastcommand == aboutCal) 
        JOptionPane.showMessageDialog(panel, "计算器开发者:赖明泉");
     }
    //输入中如果有操作非法，比如按下两次'+'，捕获异常
    catch (Exception e) {
      textAnswer.setText("操作非法");
    }
    }
    }
	
  //主函数
  public static void main(String args[]) {
    new Calculator();
  }
}