importjava.awt.*;importjava.awt.event.*;importjava.lang.*;importjavax.swing.*;publicclassCounterextendsFrame{//声明三个面板的布局GridLayoutgl1,gl2,gl3;Panelp0,p1,p2,p3;JTextFieldtf1;TextFieldtf2;Buttonb0,b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17,b18,b19,b20,b21,b22,b23,b24,b25,b26;StringBufferstr;//显示屏所显示的字符串doublex,y;//x和y都是运算数intz;//Z表示单击了那一个运算符.0表示"+",1表示"-",2表示"*",3表示"/"staticdoublem;//记忆的数字publicCounter(){gl1=newGridLayout(1,4,10,0);//实例化三个面板的布局gl2=newGridLayout(4,1,0,15);gl3=newGridLayout(4,5,10,15);tf1=newJTextField(27);//显示屏tf1.setHorizontalAlignment(JTextField.RIGHT);tf1.setEnabled(false);tf1.setText("0");tf2=newTextField(10);//显示记忆的索引值tf2.setEditable(false);//实例化所有按钮、设置其前景色并注册监听器b0=newButton("Backspace");b0.setForeground(Color.red);b0.addActionListener(newBt());b1=newButton("CE");b1.setForeground(Color.red);b1.addActionListener(newBt());b2=newButton("C");b2.setForeground(Color.red);b2.addActionListener(newBt());b3=newButton("MC");b3.setForeground(Color.red);b3.addActionListener(newBt());b4=newButton("MR");b4.setForeground(Color.red);b4.addActionListener(newBt());b5=newButton("MS");b5.setForeground(Color.red);b5.addActionListener(newBt());b6=newButton("M+");b6.setForeground(Color.red);b6.addActionListener(newBt());b7=newButton("7");b7.setForeground(Color.blue);b7.addActionListener(newBt());b8=newButton("8");b8.setForeground(Color.blue);b8.addActionListener(newBt());b9=newButton("9");b9.setForeground(Color.blue);b9.addActionListener(newBt());b10=newButton("/");b10.setForeground(Color.red);b10.addActionListener(newBt());b11=newButton("sqrt");b11.setForeground(Color.blue);b11.addActionListener(newBt());b12=newButton("4");b12.setForeground(Color.blue);b12.addActionListener(newBt());b13=newButton("5");b13.setForeground(Color.blue);b13.addActionListener(newBt());b14=newButton("6");b14.setForeground(Color.blue);b14.addActionListener(newBt());b15=newButton("*");b15.setForeground(Color.red);b15.addActionListener(newBt());b16=newButton("%");b16.setForeground(Color.blue);b16.addActionListener(newBt());b17=newButton("1");b17.setForeground(Color.blue);b17.addActionListener(newBt());b18=newButton("2");b18.setForeground(Color.blue);b18.addActionListener(newBt());b19=newButton("3");b19.setForeground(Color.blue);b19.addActionListener(newBt());b20=newButton("-");b20.setForeground(Color.red);b20.addActionListener(newBt());b21=newButton("1/X");b21.setForeground(Color.blue);b21.addActionListener(newBt());b22=newButton("0");b22.setForeground(Color.blue);b22.addActionListener(newBt());b23=newButton("+/-");b23.setForeground(Color.blue);b23.addActionListener(newBt());b24=newButton(".");b24.setForeground(Color.blue);b24.addActionListener(newBt());b25=newButton("+");b25.setForeground(Color.red);b25.addActionListener(newBt());b26=newButton("=");b26.setForeground(Color.red);b26.addActionListener(newBt());//实例化四个面板p0=newPanel();p1=newPanel();p2=newPanel();p3=newPanel();//创建一个空字符串缓冲区str=newStringBuffer();//添加面板p0中的组件和设置其在框架中的位置和大小p0.add(tf1);p0.setBounds(10,25,300,40);//添加面板p1中的组件和设置其在框架中的位置和大小p1.setLayout(gl1);p1.add(tf2);p1.add(b0);p1.add(b1);p1.add(b2);p1.setBounds(10,65,300,25);//添加面板p2中的组件并设置其的框架中的位置和大小p2.setLayout(gl2);p2.add(b3);p2.add(b4);p2.add(b5);p2.add(b6);p2.setBounds(10,110,40,150);//添加面板p3中的组件并设置其在框架中的位置和大小p3.setLayout(gl3);//设置p3的布局p3.add(b7);p3.add(b8);p3.add(b9);p3.add(b10);p3.add(b11);p3.add(b12);p3.add(b13);p3.add(b14);p3.add(b15);p3.add(b16);p3.add(b17);p3.add(b18);p3.add(b19);p3.add(b20);p3.add(b21);p3.add(b22);p3.add(b23);p3.add(b24);p3.add(b25);p3.add(b26);p3.setBounds(60,110,250,150);//设置框架中的布局为空布局并添加4个面板setLayout(null);add(p0);add(p1);add(p2);add(p3);setResizable(false);//禁止调整框架的大小//匿名类关闭窗口addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente1){System.exit(0);}});setBackground(Color.lightGray);setBounds(100,100,320,280);setVisible(true);}//构造监听器classBtimplementsActionListener{publicvoidactionPerformed(ActionEvente2){try{if(e2.getSource()==b1)//选择"CE"清零{tf1.setText("0");//把显示屏清零str.setLength(0);//清空字符串缓冲区以准备接收新的输入运算数}elseif(e2.getSource()==b2)//选择"C"清零{tf1.setText("0");//把显示屏清零str.setLength(0);}elseif(e2.getSource()==b23)//单击"+/-"选择输入的运算数是正数还是负数{x=Double.parseDouble(tf1.getText().trim());tf1.setText(""+(-x));}elseif(e2.getSource()==b25)//单击加号按钮获得x的值和z的值并清空y的值{x=Double.parseDouble(tf1.getText().trim());str.setLength(0);//清空缓冲区以便接收新的另一个运算数y=0d;z=0;}elseif(e2.getSource()==b20)//单击减号按钮获得x的值和z的值并清空y的值{x=Double.parseDouble(tf1.getText().trim());str.setLength(0);y=0d;z=1;}elseif(e2.getSource()==b15)//单击乘号按钮获得x的值和z的值并清空y的值{x=Double.parseDouble(tf1.getText().trim());str.setLength(0);y=0d;z=2;}elseif(e2.getSource()==b10)//单击除号按钮获得x的值和z的值并空y的值{x=Double.parseDouble(tf1.getText().trim());str.setLength(0);y=0d;z=3;}elseif(e2.getSource()==b26)//单击等号按钮输出计算结果{str.setLength(0);switch(z){case0:tf1.setText(""+(x+y));break;case1:tf1.setText(""+(x-y));break;case2:tf1.setText(""+(x*y));break;case3:tf1.setText(""+(x/y));break;}}elseif(e2.getSource()==b24)//单击"."按钮输入小数{if(tf1.getText().trim().indexOf(′.′)!=-1)//判断字符串中是否已经包含了小数点{}else//如果没数点有小{if(tf1.getText().trim().equals("0"))//如果初时显示为0{str.setLength(0);tf1.setText((str.append("0"+e2.getActionCommand())).toString());}elseif(tf1.getText().trim().equals(""))//如果初时显示为空则不做任何操作{}else{tf1.setText(str.append(e2.getActionCommand()).toString());}}y=0d;}elseif(e2.getSource()==b11)//求平方根{x=Double.parseDouble(tf1.getText().trim());tf1.setText("数字格式异常");if(x<0)tf1.setText("负数没有平方根");elsetf1.setText(""+Math.sqrt(x));str.setLength(0);y=0d;}elseif(e2.getSource()==b16)//单击了"%"按钮{x=Double.parseDouble(tf1.getText().trim());tf1.setText(""+(0.01*x));str.setLength(0);y=0d;}elseif(e2.getSource()==b21)//单击了"1/X"按钮{x=Double.parseDouble(tf1.getText().trim());if(x==0){tf1.setText("除数不能为零");}else{tf1.setText(""+(1/x));}str.setLength(0);y=0d;}elseif(e2.getSource()==b3)//MC为清除内存{m=0d;tf2.setText("");str.setLength(0);}elseif(e2.getSource()==b4)//MR为重新调用存储的数据{if(tf2.getText().trim()!="")//有记忆数字{tf1.setText(""+m);}}elseif(e2.getSource()==b5)//MS为存储显示的数据{m=Double.parseDouble(tf1.getText().trim());tf2.setText("M");tf1.setText("0");str.setLength(0);}elseif(e2.getSource()==b6)//M+为将显示的数字与已经存储的数据相加要查看新的数字单击MR{m=m+Double.parseDouble(tf1.getText().trim());}else//选择的是其他的按钮{if(e2.getSource()==b22)//如果选择的是"0"这个数字键{if(tf1.getText().trim().equals("0"))//如果显示屏显示的为零不做操作{}else{tf1.setText(str.append(e2.getActionCommand()).toString());y=Double.parseDouble(tf1.getText().trim());}}elseif(e2.getSource()==b0)//选择的是“BackSpace”按钮{if(!tf1.getText().trim().equals("0"))//如果显示屏显示的不是零{if(str.length()!=1){tf1.setText(str.delete(str.length()-1,str.length()).toString());//可能抛出字符串越界异常}else{tf1.setText("0");str.setLength(0);}}y=Double.parseDouble(tf1.getText().trim());}else//其他的数字键{tf1.setText(str.append(e2.getActionCommand()).toString());y=Double.parseDouble(tf1.getText().trim());}}}catch(NumberFormatExceptione){tf1.setText("数字格式异常");}catch(StringIndexOutOfBoundsExceptione){tf1.setText("字符串索引越界");}}}publicstaticvoidmain(Stringargs[]){newCounter();}}
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