calculator.java

实现了计算器的简单功能,算自己开始编程的处女作

					    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;
  		}
   	      //'%'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 
		    {
        		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
   	     //'MC'的操作，将内存清0
   	      if (temp == buttonMC && clickable == true) 
		{
      		   memoryd = memoryi = 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) 
		{
      		    boolean isDot = false;
      		    textMemory.setText("   M");
      	 	    for (int i = 0; i < textAnswer.getText().length(); i++)
      		    if ('.' == textAnswer.getText().charAt(i)) 
		      {
       			isDot = true;
      			break;
    		       }
   	           //如果是double,则存入memoryd(double存储器)
      		    if (isDot == true) 
      		      {
     			memoryd = Double.parseDouble(textAnswer.getText());
          		memoryi = 0; //保证存储器中存放最新的值
      			}
     		    //如果是int,则存入memoryi(int存储器)
      		    else 
		      {
      			memoryi = Integer.parseInt(textAnswer.getText());
       			memoryd = 0; //保证存储器中存放最新的值
      			}
     		 }
    	     //'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));
     		   if (memoryi != 0)
      			textAnswer.setText(Integer.toString(memoryi));
   		}
    	     //'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) 
     		{
     		    boolean isDot = false;
   		    for(int i = 0; i < textAnswer.getText().length(); i++)
      			if ('.' == textAnswer.getText().charAt(i)) 
			  {
         			isDot = true;
           			break;
       			   }
      		    if (memoryi != 0) 
		      { //存储中是一个int型数
      			if (isDot == false) //被加数是一个int型数
        		    memoryi += Integer.parseInt(textAnswer.getText());
      			else 
			  { //被加数是一个double型数，则将int存储器中数传入double存储器与当前数相加，			    //　int存储器清零
     			     memoryd = memoryi + Double.parseDouble(textAnswer.getText());
      			    memoryi = 0;
        		   }
      		       }
       		    else
       			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;
  		}
    	     //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);
    		}
     	     if (temp == 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 (temp == topHelp) 
		{
   		   JOptionPane.showMessageDialog(panel, scrollHelp);
   		}
      	 	//按下'数字分组'菜单栏
     	     if (temp == 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 (temp == aboutCal) 
		{
   		   JOptionPane.showMessageDialog(panel, "计算器1.00版\n开发者：楼竞");
  		}
 	    }
 	  //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;
  		}
	}
  //主函数
  public static void main(String args[]) 
	{
  		new Calculator();
 	}
 }