calculator.java

计算器程序

              			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;
  			}
      		//'%'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\n开发者：陈方超");
      		}
    	}
    	//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();
  	}
}