Java 计算器｜8月更文挑战

这是我参与8月更文挑战的第17天，活动详情查看：8月更文挑战

通过UI点击按钮计算

UI虽丑，但五脏俱全！

代码实现

package calculation5;

import javax. swing. *;
import java. awt. *;
import java. awt. event. *;

public class Calculation5 extends JFrame implements ActionListener{
	private static final long serialVersionUID = 1L;
	//实现序列化,serialVersionUID 用来表明实现序列化类的不同版本间的兼容性

	JTextField x; //文本框
    String preOperater=""; //上一次的运算符
    double sum=0; //运算结果

public Calculation5 (String title) {
	super(title) ;
	Container c=getContentPane(); //容器
    c. setLayout (new BorderLayout()); //容器采用边缘布局
    x=new JTextField(50);
    c. add("North",x);
    	      String buttoned[]={"0","1","2","3","+/-",".","C","退格","倒数",
    	    		  "4","5","6","7","+","-","*","/","%",
    	    		  "8","9","=","sqrt","pow","log","cos","tan","exp"};

    	      JPanel p=new JPanel(); //面板
    	      p. setLayout (new GridLayout (3, 9, 10, 10)); //面板采用行列数3, 9的网格布局
    	      for(int k=0;k<buttoned. length;k++) { //用一个for循环将按钮添加进面板并注册监听器
    	      JButton b=new JButton (buttoned[k]);
    	      p. add (b);
    	      b. addActionListener(this); }
    	      
    	      c. add("Center",p);
    	     
    	      this. setDefaultCloseOperation (JFrame. EXIT_ON_CLOSE);}//响应用户事件，根据点击按钮实现相关操作
    	      public void actionPerformed(ActionEvent e) {
    	      String Command=e. getActionCommand() ;
    	              try{
    	                       if (Character.isDigit (Command.charAt(0))){ //如果按钮事件为数字键
    	                    	   x. setText (x. getText () +Command); //添加数字
    	                       }

    	      else if (Command. equals(".")){ //如果按钮事件为”.”键
    	    	  xiaoshu();}

    	      else if(Command. equals("+/-")) { //如果按钮事件为”+/-”键"
    	      		fuhao();}

    	      else if (Command. equals("退格")){ //如果按钮事件为”退格”键
    	      backspace() ;}

    	      else if (Command. equals("=")){ //如果按钮事件为"=”键
    	      dengyu();}

    	      else if(Command. equals("sqrt")){ //如果按钮事件为"sqrt"键
    	      sqrt();}

    	      else if(Command. equals(" log")) { //如果按钮事件为"1og”键
    	    	  log();}

    	      else if (Command. equals("cos")){ //如果按钮事件为"cos”键
    	    	  cos();}

    	      else if (Command. equals("tan")){ //如果按钮事件为”tan”键
    	    	  tan();}
    	      
    	      else if (Command. equals("exp")){ //如果按钮事件为"exp”键
    	    	  exp();}

    	      else if (Command. equals("倒数")) { //如果按钮事件为”求倒”键"
    	          		qiudao();}

    	      else if (Command. equals("C")){ //如果按钮事件为"C"键
    	    	  clear() ;}

    	      else { doOperation(); //记录运算符和输入的数字
    	          x. setText("");
    	          preOperater= Command;}}catch(Exception ex) {
    	        	  sum=0; 
    	        	  x. setText("");}}
    	          
void xiaoshu() { //添加小数点

    	          String s=x. getText();
    	          if(s.indexOf(".")==-1)x. setText(s+".");}

void fuhao() { //添加负号
    	        	  String s=x. getText();
    	        	  if (s. indexOf("-")==-1)
    	        		   x. setText("-"+x. getText());
    	        	 }

void backspace(){ //退格
    	    	   String s=x. getText();
    	    	   if(s. length()>0)
    	          x. setText (s. substring(0, s. length()-1));} //删除最后-一个字符
    	       
void dengyu(){ //等号，显示计算结果
    	          doOperation();
    	          x. setText("" +sum) ; preOperater="";}

void sqrt(){ //求该数的平方根
    	          double m=Double. parseDouble (x. getText());
    	          if (m<0) 
    	          x. setText("负数不能开根号");
    	          else
    	          x. setText(""+Math. sqrt(m)); }

void log() { //求该数的自然对数
    	          double m= Double. parseDouble(x. getText());
    	          if (m<0)
    	          x. setText("负数不能进行自然对数运算");
    	          else
    	          x. setText("" +Math. log(m)); }

void cos() { //求该数的余弦
double m=Double. parseDouble(x. getText());
x. setText("" +Math. cos(m));}

void tan() {//求该数的正切 
double m=Double. parseDouble (x. getText());
x. setText(""+Math. tan(m));}

void exp() { //求e的幂
double m=Double. parseDouble(x. getText());
x. setText("" +Math. exp (m)) ;}

void qiudao() { //求倒数
if (Double. parseDouble(x. getText())==0)
	x. setText("除数不能为零");
else {
x. setText(" "+1/ (Double. parseDouble(x. getText())));
    	          preOperater="" ;}}

void clear() { //清零
	sum=0;
    x. setText("");
    preOperater="" ;}

    //根据记录的运算符将前面记录的结果sum与文本框中的数据进行运算
void doOperation() {

    double m=Double. parseDouble(x. getText());

    if (preOperater. equals("")) sum=m;//将结果与文本框中的数据按照前一个运算符运算
    if (preOperater. equals("+")) sum=sum+m;//加法运算
    if (preOperater. equals("-")) sum=sum-m; //减法运算
    if (preOperater. equals("*")) sum=sum*m; //乘法运算
    if (preOperater. equals("/")) sum=sum/m; //除法运算
    if (preOperater. equals("%")) sum=sum%m; //求余
    if (preOperater. equals("pow")) sum=Math. pow(sum, m);} //求幂
    
    public static void main(String a[]){
    	JFrame x=new Calculation5("计算器");
    x.setSize(650,300);
    x.setVisible(true);}}