计算器退格java代码 电脑计算器怎么退格
java编写计算器实现退格，倒数，小数点，正负号功能代码
import java.awt.*;
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import java.awt.event.*;
import javax.swing.*;
class General extends JFrame implements ActionListener
{
String args[]={"退格","总清","清零","/","1","2","3","+","4","5","6","-","7","8","9","*","0","+/-",".","="};
JButton jb[]=new JButton[20];
JPanel p1=new JPanel();
JTextField jtf=new JTextField(15);
double num1,num2,jieguo;
char c,ch;
public General()
{
Container ct=getContentPane();
jtf.addKeyListener(new KA());
jtf.setHorizontalAlignment(JTextField.RIGHT);
ct.add(jtf,"North");
p1.setLayout(new GridLayout(5,4));
for(int i=0;i20;i++)
{
jb[i]=new JButton(args[i]);
jb[i].addActionListener(this);
p1.add(jb[i]);
}
ct.add(p1);
pack();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String args[])
{
new General();
}
public void actionPerformed(ActionEvent e)// 监听按键
{
String str=e.getActionCommand().trim();
if("0123456789.".indexOf(str)!=-1)
{
if(jtf.getText().equals("0"))jtf.setText(null);
jtf.setText(jtf.getText()+str);
return;
}
if("+-*/".indexOf(str)!=-1)
{
num1=Double.parseDouble(jtf.getText());
c=str.charAt(0);
jtf.setText(null);
return;
}
else if(str.equals("="))
{
num2=Double.parseDouble(jtf.getText());
switch(c)
{
case '+': jieguo=num1+num2; break;
case '-': jieguo=num1-num2; break;
case '*': jieguo=num1*num2; break;
case '/': jieguo=num1/num2; break;
}
jtf.setText(Double.toString(jieguo));
}
else if(str.equals("+/-"))
{
if(jtf.getText().isEmpty()==false)
{
Double lnum=-(Double.parseDouble(jtf.getText()));
jtf.setText(Double.toString(lnum));
}
else
{
jtf.setText("-");
}
}
else if(str.equals("清空"))
{
jtf.setText(null);
}
else if(str.equals("清零"))
{
jtf.setText("0");
}
else if(str.equals("退格"))
{
jtf.setText(jtf.getText().substring(0,jtf.getText().length()-1));
}
}
class KA extends KeyAdapter // 监听键盘
{
public void keyPressed(KeyEvent e)
{
char ch=e.getKeyChar();
if("+-*/".indexOf(ch)!=-1)
{
num1=Double.parseDouble(jtf.getText());
c=ch;
}
if(ch=='='|ch==e.VK_ENTER)
{
num2=Double.parseDouble(jtf.getText());
switch(c)
{
case '+': jieguo=num1+num2; break;
case '-': jieguo=num1-num2; break;
case '*': jieguo=num1*num2; break;
case '/': jieguo=num1/num2; break;
}
}
}
public void keyReleased(KeyEvent e)
{
char ch=e.getKeyChar();
if("+-*/".indexOf(ch)!=-1)
{
jtf.setText(null);
}
if(ch=='='|e.getKeyCode()==e.VK_ENTER)
{
jtf.setText(Double.toString(jieguo));
}
}
}
}
java 写计算器的退格键怎么写，如“123456”按下退格变“12345”
String str = "12345";
str = str.substring(0, str.length()-1);
int a = Integer.parseInt(str);
怎么用JAVA编写一个计算器窗口，并实现他的功能，求给出代码，对的话一定高分回报，谢谢了。。。
JAVA 计算器程序
Cadev.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.LinkedList;
import java.text.NumberFormat;
import javax.swing.border.*;
public class Cadev extends JFrame implements ActionListener
{
Nbtn nbtn[];
Obtn obtn[];
Button dotbtn,PlusOrMinusbtn,Backspacebtn,
recbtn,equbtn,clbtn;
JPanel panel;
JTextField resultShow;
String Oper[]={"+","-","*","/"};
LinkedList link;
boolean sfcequ=false;
public Cadev()
{
super("计算器");
link=new LinkedList();
nbtn=new Nbtn[10];
for(int i=0;i=9;i++)
{
nbtn[i]=new Nbtn(i);
nbtn[i].addActionListener(this);
}
obtn=new Obtn[4];
for(int i=0;i4;i++)
{
obtn[i]=new Obtn(Oper[i]);
obtn[i].addActionListener(this);
}
dotbtn=new Button(".");
PlusOrMinusbtn=new Button("+/-");
equbtn=new Button("=");
recbtn=new Button("1/x");
Backspacebtn=new Button("退格");
clbtn=new Button("C");
recbtn.setForeground(Color.blue);
dotbtn.setForeground(Color.blue);
PlusOrMinusbtn.setForeground(Color.blue);
equbtn.setForeground(Color.red);
Backspacebtn.setForeground(Color.red);
clbtn.setForeground(Color.red);
dotbtn.addActionListener(this);
PlusOrMinusbtn.addActionListener(this);
equbtn.addActionListener(this);
recbtn.addActionListener(this);
Backspacebtn.addActionListener(this);
clbtn.addActionListener(this);
resultShow=new JTextField(10);
resultShow.setHorizontalAlignment(JTextField.RIGHT);
resultShow.setFont(new Font("TimesRoman",Font.PLAIN,14));
resultShow.setBorder(new SoftBevelBorder(BevelBorder.LOWERED));
resultShow.setBackground(Color.white);
resultShow.setEditable(false);
panel=new JPanel();
panel.setLayout(new GridLayout(4,5));
panel.add(nbtn[1]);
panel.add(nbtn[2]);
panel.add(nbtn[3]);
panel.add(obtn[0]);
panel.add(clbtn);
panel.add(nbtn[4]);
panel.add(nbtn[5]);
panel.add(nbtn[6]);
panel.add(obtn[1]);
panel.add(Backspacebtn);
panel.add(nbtn[7]);
panel.add(nbtn[8]);
panel.add(nbtn[9]);
panel.add(obtn[2]);
panel.add(recbtn);
panel.add(nbtn[0]);
panel.add(PlusOrMinusbtn);
panel.add(dotbtn);
panel.add(obtn[3]);
panel.add(equbtn);
add(panel,BorderLayout.CENTER);
add(resultShow,BorderLayout.NORTH);
addWindowListener(new WindowAdapter()
{ public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
setVisible(true);
setBounds(100,50,240,180);
setResizable(false);
validate();
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource() instanceof Nbtn)
{
Nbtn b=(Nbtn)e.getSource();
if(link.size()==0)
{
int num=b.getNum();
link.add(""+num);
resultShow.setText(""+num);
sfcequ=false;
}
else if(link.size()==1sfcequ==false)
{
int num=b.getNum();
String Number=(String)link.getFirst();
String s=Number.concat(""+num);
link.set(0,s);
resultShow.setText(s);
}
else if(link.size()==1sfcequ==true)
{
int num=b.getNum();
link.removeFirst();
link.add(""+num);
sfcequ=false;
resultShow.setText(""+num);
}
else if(link.size()==2)
{
int num=b.getNum();
link.add(""+num);
resultShow.setText(""+num);
}
else if(link.size()==3)
{
int num=b.getNum();
String Number=(String)link.getLast();
String s=Number.concat(""+num);
link.set(2,s);
resultShow.setText(s);
}
}
else if(e.getSource() instanceof Obtn)
{
Obtn b=(Obtn)e.getSource();
if(link.size()==1)
{
String sign=b.getOper();
link.add(sign);
}
else if(link.size()==2)
{
String sign=b.getOper();
link.set(1,sign);
}
else if(link.size()==3)
{
String sign=b.getOper();
String num1=(String)link.getFirst();
String num2=(String)link.getLast();
String Oper=(String)link.get(1);
try
{
double n1=Double.parseDouble(num1);
double n2=Double.parseDouble(num2);
double n=0;
if(Oper.equals("+"))
{
n=n1+n2;
}
else if(Oper.equals("-"))
{
n=n1-n2;
}
else if(Oper.equals("*"))
{
n=n1*n2;
}
else if(Oper.equals("/"))
{
n=n1/n2;
}
link.clear();
link.add(""+n);
link.add(sign);
resultShow.setText(""+n);
}
catch(Exception ee)
{
}
}
}
else if(e.getSource()==equbtn)
{
sfcequ=true;
if(link.size()==1||link.size()==2)
{
String num=(String)link.getFirst();
resultShow.setText(""+num);
}
else if(link.size()==3)
{
String num1=(String)link.getFirst();
String num2=(String)link.getLast();
String sign=(String)link.get(1);
try
{
double n1=Double.parseDouble(num1);
double n2=Double.parseDouble(num2);
double n=0;
if(sign.equals("+"))
{
n=n1+n2;
}
else if(sign.equals("-"))
{
n=n1-n2;
}
else if(sign.equals("*"))
{
n=n1*n2;
}
else if(sign.equals("/"))
{
n=n1/n2;
}
resultShow.setText(""+n);
link.set(0,""+n);
link.removeLast();
link.removeLast();
}
catch(Exception ee)
{
}
}
}
else if(e.getSource()==dotbtn)
{
if(link.size()==0)
{
sfcequ=false;
}
else if(link.size()==1)
{
String dot=dotbtn.getLabel();
String num=(String)link.getFirst();
String s=null;
if(num.indexOf(dot)==-1)
{
s=num.concat(dot);
link.set(0,s);
}
else
{
s=num;
}
link.set(0,s);
resultShow.setText(s);
}
else if(link.size()==3)
{
String dot=dotbtn.getLabel();
String num=(String)link.getLast();
String s=null;
if(num.indexOf(dot)==-1)
{
s=num.concat(dot);
link.set(2,s);
}
else
{
s=num;
}
resultShow.setText(s);
}
}
else if(e.getSource()==Backspacebtn)
{
if(link.size()==1)
{
String num=(String)link.getFirst();
if(num.length()=1)
{
num=num.substring(0,num.length()-1);
link.set(0,num);
resultShow.setText(num);
}
else
{
link.removeLast();
resultShow.setText("0");
}
}
else if(link.size()==3)
{
String num=(String)link.getLast();
if(num.length()=1)
{
num=num.substring(0,num.length()-1);
link.set(0,num);
resultShow.setText(num);
}
else
{
link.removeLast();
resultShow.setText("0");
}
}
}
else if(e.getSource()==PlusOrMinusbtn)
{
if(link.size()==1)
{
String num1=(String)link.getFirst();
try
{
double d=Double.parseDouble(num1);
d=-1*d;
String str=String.valueOf(d);
link.set(0,str);
resultShow.setText(str);
}
catch(Exception ee)
{
}
}
else if(link.size()==3)
{
String num2=(String)link.getLast();
try
{
double d=Double.parseDouble(num2);
d=-1*d;
String str=String.valueOf(d);
link.set(2,str);
resultShow.setText(str);
}
catch(Exception ee)
{
}
}
}
else if(e.getSource()==recbtn)
{
if(link.size()==1||link.size()==2)
{
String num1=(String)link.getFirst();
try
{
double d=Double.parseDouble(num1);
d=1.0/d;
String str=String.valueOf(d);
link.set(0,str);
resultShow.setText(str);
}
catch(Exception ee)
{
}
}
else if(link.size()==3)
{
String num2=(String)link.getLast();
try
{
double d=Double.parseDouble(num2);
d=1.0/d;
String str=String.valueOf(d);
link.set(0,str);
}
catch(Exception ee)
{
}
}
}
else if(e.getSource()==clbtn)
{
sfcequ=false;
resultShow.setText("0");
link.clear();
}
}
public static void main(String agrs[])
{
new Cadev();
}
}
Nbtn.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Nbtn extends Button
{
int Num;
public Nbtn(int n)
{
super(""+n);
Num=n;
setForeground(Color.blue);
}
public int getNum()
{
return Num;
}
}
Obtn.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Obtn extends Button
{
String Oper;
public Obtn(String s)
{
super(s);
Oper=s;
setForeground(Color.red);
}
public String getOper()
{
return Oper;
}
}
高分求 用JAVA编写计算器界面(只要界面)代码!
package importantpg;
import java.awt.*;
import java.awt.event.*;
public class jisuanqi
{
TextArea tf=new TextArea(3,50 );
Button lb=new Button("clear");
Panel p1=new Panel();
Panel p2=new Panel();
public jisuanqi()
{ Frame f=new Frame("计算器");
Panel p=new Panel();
f.setBackground(Color.white);
f.setSize(500, 1500);
f.setVisible(true);
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e) {System.exit(1);}
});
Button[] b=new Button[18]; b[10]=new Button("-"); b[15]=new Button("(");
b[11]=new Button("+"); b[12]=new Button("*"); b[16]=new Button(")");
b[13]=new Button("/"); b[14]=new Button("="); b[17]=new Button("退格");
for(int i=0;i=9;++i)
{
b[i]=new Button(""+i);
}
p.setLayout(new GridLayout(6,3));
avent aa=new avent();
lb.addActionListener(aa);
for(int i=0;i18;++i)
{
p.add(b[i]);b[i].addActionListener(aa);
}
p1.setLayout(new BorderLayout());
p1.add(lb,"North");p1.add(tf,"South");f.add(p1, "South");
f.add(p,"Center"); f.pack();
} //构造方法
public static void main(String args[])
{
new jisuanqi();
}
class avent implements ActionListener //事件体
{
public void actionPerformed(ActionEvent e)
{
String s=null; String in="";
s=e.getActionCommand();
if (s!="="s!=nulls!="clear"s!="退格")
{
tf.append(s);
in+=s; s=null;
}
else if(s=="clear")
{
tf.replaceRange("",0,1000);
}else if(s=="=")
{
tf.append("="+jisuan(tf.getText()));
}
else if(s=="退格") {}
}///////////////////////////////////////////////事件处理方法
}
///////////////////////////////////////计算过程//////////////
static String jisuan(String s)
{
String hs= "";
char[] ch = new char[s.length()];
int top = -1;
for (int i = 0; i s.length(); i++)
{
char rsc = s.charAt(i);
switch(rsc)
{
case ' ' : break;
case '+' : //操作符
case '-' :
while (top = 0) //栈不为空时
{
char pc = ch[top--]; //pop Operator
if (pc == '(')
{
ch[++top] = pc; //push Operator
break;
}
else {hs = hs + pc;}
}
ch[++top] = rsc; //push Operator
hs += " ";break;
case '*' : //操作符
case '/' :
while (top = 0) //栈不为空时
{
char c = ch[top--]; //pop Operator
if (c == '(')
{
ch[++top] = c; //push Operator
break;
}
else
{
if (c == '+' || c == '-')
{
ch[++top] = c; //push Operator
break;
}
else
{
hs = hs + c;
}
}
}
ch[++top] = rsc; //push Operator
hs += " ";
break;
case '(' : //操作符
ch[++top] = rsc;
hs+= " ";
break;
case ')' : //操作符
while (top = 0) //栈不为空时
{
char c = ch[top--]; //pop Operator
if (c == '(')
{
break;
}
else
{
hs= hs + c;
}
}
hs += " ";
break;
default : //操作数
hs= hs + rsc;
break;
}//switch
}/////////////////////////////for
while (top = 0)
{
hs= hs + ch[top--]; //pop Operator
}
//System.out.println("hs="+hs); //后缀
//////////////////////////////////////////////后缀////////////////////////////////////
//后缀表达式计算
double[] result = new double[hs.length()];
double x, y;
top = - 1;
String st = "";
for (int i = 0; i hs.length(); i++)
{
char c = hs.charAt(i);
if ((c = '0' c = '9') || c == '.')
{
st += c;
}
if ((c == ' ' st != "") || i == hs.length() - 1)
{
result[++top] = Double.parseDouble(st) ; //push Operands
st = "";
}
if (c == '+' || c == '-' || c == '*' || c == '/')
{
if ((st != ""))
{
result[++top] =Double.parseDouble(st) ; //push Operands
st = "";
}
y = result[top--];
x = result[top--];
switch (c)
{
case '+' :
result[++top] = x+y;break;//push 中间结果再次入栈
case '-' :
result[++top] = x-y;break;
case '*' :
result[++top] = x*y;break;
case '/' :
result[++top] = x/y;break;
default :break;
}
}////////////////////if
} ///////////////////////for
return String.valueOf(result[top]); //pop 最终结果
} /////////////////////////jisuan
}
本文题目：计算器退格java代码 电脑计算器怎么退格
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