calculator.java

Java编写的计算器程序

            case 1:
              answerd -= Double.parseDouble(textAnswer.getText());
              break;
            case 2:
              answerd *= Double.parseDouble(textAnswer.getText());
              break;
            case 3:
              if (Double.parseDouble(textAnswer.getText()) == 0) 
              {
                textAnswer.setText("除数不能为零");
                clickable = false;
              }
              else
                answerd /= Double.parseDouble(textAnswer.getText());
              break;
            default:
              answerd = Double.parseDouble(textAnswer.getText());
          }
          textAnswer.setText("");
          prekey = key = 2;
        }
        //'/'操作
        if (temp == buttonDiv) 
        {
          switch (prekey) 
          {
            case 0:
              answerd += Double.parseDouble(textAnswer.getText());
              break;
            case 1:
              answerd -= Double.parseDouble(textAnswer.getText());
              break;
            case 2:
              answerd *= Double.parseDouble(textAnswer.getText());
              break;
            case 3:
              if (Double.parseDouble(textAnswer.getText()) == 0) 
              {
                textAnswer.setText("除数不能为零");
                clickable = false;
              }
              else
                answerd /= Double.parseDouble(textAnswer.getText());
              break;
            default:
              answerd = Double.parseDouble(textAnswer.getText());
          }
          textAnswer.setText("");
          prekey = key = 3;
        }
      }
      //'='操作
      if (temp == buttonEqual && clickable == true) 
      {
        //如果连续按'=',则进行连续运算
        if (prekey == 5) 
        {
          if (key == 0) 
          {
            answerd += vard;
            textAnswer.setText(df.format(answerd));
          }
          if (key == 1) 
          {
            answerd -= vard;
            textAnswer.setText(df.format(answerd));
          }
          if (key == 2) 
          {
            answerd *= vard;
            textAnswer.setText(df.format(answerd));
          }
          if (key == 3) 
          {
            if (Double.parseDouble(textAnswer.getText()) == 0) 
            {
              textAnswer.setText("除数不能为零");
              clickable = false;
            }
            else 
            {
              answerd /= vard;
              textAnswer.setText(df.format(answerd));
            }
          }
        }
        else 
        {
          vard = Double.parseDouble(textAnswer.getText());
          if (key == 0) 
          {
            prekey = -1;
            answerd += Double.parseDouble(textAnswer.getText());
            textAnswer.setText(df.format(answerd));
          }
          if (key == 1) 
          {
            prekey = -1;
            answerd -= Double.parseDouble(textAnswer.getText());
            textAnswer.setText(df.format(answerd));
          }
          if (key == 2) 
          {
            prekey = -1;
            answerd *= Double.parseDouble(textAnswer.getText());
            textAnswer.setText(df.format(answerd));
          }
          if (key == 3) 
          {
            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;
      }
      //sin运算
      if (temp == buttonSin && clickable == true)
      {
      	String s = textAnswer.getText();
      	double d = Double.parseDouble(s);
      	d *= Math.PI / 180;
      	textAnswer.setText(Double.toString(java.lang.Math.sin(d)));
      }
      //cos运算
      if (temp == buttonCos && clickable == true)
      {
      	String s = textAnswer.getText();
      	double d = Double.parseDouble(s);
      	d *= Math.PI / 180;
      	textAnswer.setText(Double.toString(java.lang.Math.cos(d)));
      }
      //阶乘运算
      if (temp == buttonJie && clickable == true)
      {
      	String s = textAnswer.getText();
        double d = Double.parseDouble(s);
		d = jc.f(d);       
        textAnswer.setText(String.valueOf(d));
      }      
      //平方运算
      if (temp == buttonFang && clickable == true)
      {
      	String s = textAnswer.getText();
        textAnswer.setText(Double.toString(java.lang.Math.pow(Double.
            parseDouble(textAnswer.getText()),2)));
      }
      //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 
        {
          boolean isDec = true;
          int i, j, k;
          String s = Double.toString(1 / Double.parseDouble(textAnswer.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);
            textAnswer.setText(stemp);
          }
          else
            textAnswer.setText(s);
        }
      }
      //按下'+/-'按钮时处理
      if (temp == buttonAddAndSub && clickable == true) 
      {
        boolean isNumber = true;
        String s = textAnswer.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) 
        {
          //如果当前字符串首字母有'-'号,代表现在是个负数,再按下时,则将首符号去掉
          if (s.charAt(0) == '-') 
          {
            textAnswer.setText("");
            for (int i = 1; i < s.length(); i++) 
            {
              char a = s.charAt(i);
              textAnswer.setText(textAnswer.getText() + a);
            }
          }
          //如果当前字符串第一个字符不是符号，则添加一个符号在首字母处
          else
            textAnswer.setText('-' + s);
        }
      }
      //计算器有关内存操作
      //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'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;
      }
      //按下'复制'菜单栏
      if (temp == copyItem) 
      {
        copy = textAnswer.getText();
      }
      //按下'粘贴'菜单栏
      if (temp == pasteItem) 
      {
        textAnswer.setText(copy);
      }
      //按下'帮助主题'菜单栏
      if (temp == topHelp) 
      {
        JOptionPane.showMessageDialog(panel, scrollHelp);
      }
      //按下'开发小组'菜单栏
      if (temp == aboutCal) 
      {
        JOptionPane.showMessageDialog(panel, "小组成员：\n杜娟（20045153）\n张浩（20045132）\n李犇（20045154）\n郭忠斌（20045175）");
      }
  }
  class jiecheng 
  {
  	 double f(double d)
  	 {
  	 	if(d == 1)
        {
        	d = 1;
        }
        else
        {
        	d = d*f(d-1);
        }
        return d;
     }
  }
  //主函数
  public static void main(String args[]) 
  {
    new Calculator();
  }
}