Java上机作业，简单计算器的代码，模仿XP下普通计算器，暂没有优先级区分.
jar包下载，内有源码文件
欢迎指出各种bug，目前不完善的地方：
12-31：
由于没有对乘法精度限制，乘法次数过多后会由于内部位数过多而运行缓慢；
可能是由于字体原因，会造成不同平台上显示条长度不同，影响美观和使用；
import java.awt.*;
import java.awt.event.*;
import java.math.*;
import java.util.*;
import javax.swing.*;
class JCalculator extends JFrame implements ActionListener{
static final long serialVersionUID = 1L;
JCalculator(){
init();
setLayout(new BorderLayout());
setText();
setButton();
setKey();
}
void init(){
fnum=BigDecimal.ZERO;
snum=BigDecimal.ZERO;
buffer="0";
oprt=0;
isF=false;
isV=false;
isE=true;
}
boolean calc(){
if(oprt==0){
fnum=snum;
}else if(oprt==1){
fnum=fnum.add(snum);
}else if(oprt==2){
fnum=fnum.subtract(snum);
}else if(oprt==3){
fnum=fnum.multiply(snum);
}else if(oprt==4){
try{
fnum=fnum.divide(snum,200,RoundingMode.HALF_EVEN);
}catch(ArithmeticException ex){
init();
text.setText("Error!");
return false;
}
}else if(oprt==5){
try{
fnum=fnum.remainder(snum);
}catch(ArithmeticException ex){
init();
text.setText("Error!");
return false;
}
}
return true;
}
void show(BigDecimal num){
if(((num.stripTrailingZeros()).toPlainString()).length()<=24){
text.setText((num.stripTrailingZeros()).toPlainString());
}else{
BigDecimal topv=BigDecimal.ONE,tmp=num;
if(num.signum()<0) tmp=tmp.multiply(BigDecimal.valueOf(-1D));
if(tmp.compareTo(BigDecimal.ONE)>0){
while(tmp.compareTo(BigDecimal.ONE)>0){
tmp=tmp.divide(BigDecimal.TEN);
topv=topv.multiply(BigDecimal.TEN);
}
}else{
int tcnt=0;
while(tmp.compareTo(BigDecimal.ONE)<0){
tmp=tmp.multiply(BigDecimal.TEN);
topv=topv.divide(BigDecimal.TEN);
tcnt++;
if(tcnt>220) break;
}
}
if(num.signum()<0) tmp=tmp.multiply(BigDecimal.valueOf(-1D));
BigDecimal show=tmp.setScale(20, RoundingMode.HALF_EVEN).multiply(topv);
String Ans=show.stripTrailingZeros().toString();
if(Ans.matches("0E[-0-9]+")) Ans="0";
text.setText(Ans);
}
}
void setText(){
text=new JTextField(buffer,26);
text.setFocusable(false);
text.setHorizontalAlignment(JTextField.RIGHT);
text.setFont(new Font("Consolas",Font.PLAIN,18));
JPanel jpTF=new JPanel();
jpTF.setBorder(BorderFactory.createEmptyBorder(5, 10, 0, 10));
jpTF.add(text);
add(jpTF,BorderLayout.NORTH);
isM=new JLabel();
isM.setHorizontalAlignment(JLabel.CENTER);
}
void setButton(){
num=new JButton[10];
for(int i=0;i<10;i++){
num[i]=new JButton(""+i);
num[i].setFocusable(false);
num[i].addActionListener(this);
}
ButtonGroup bg=new ButtonGroup();
bg.add(dot=new JButton("."));
bg.add(sign=new JButton("±"));
bg.add(plus=new JButton("+"));
bg.add(subtract=new JButton("-"));
bg.add(multiply=new JButton("×"));
bg.add(divide=new JButton("÷"));
bg.add(mod=new JButton("mod"));
bg.add(enter=new JButton("="));
bg.add(cls=new JButton("C"));
bg.add(cle=new JButton("CE"));
bg.add(back=new JButton("←"));
bg.add(copy=new JButton("copy"));
bg.add(square=new JButton("x²"));
bg.add(sqrt=new JButton("√"));
bg.add(reci=new JButton("1/x"));
bg.add(ms=new JButton("MS"));
bg.add(mc=new JButton("MC"));
bg.add(mr=new JButton("MR"));
bg.add(ma=new JButton("M+"));
Enumeration<AbstractButton> bgE=bg.getElements();
while(bgE.hasMoreElements()){
AbstractButton tb=bgE.nextElement();
tb.addActionListener(this);
tb.setFocusable(false);
}
JPanel jpMB=new JPanel(new GridLayout(0,1,2,2));
jpMB.setBorder(BorderFactory.createEmptyBorder(5, 10, 10, 2));
jpMB.add(isM);
jpMB.add(mc);
jpMB.add(mr);
jpMB.add(ms);
jpMB.add(ma);
add(jpMB,BorderLayout.WEST);
JPanel jpNB=new JPanel(new GridLayout(0,5,2,2));
jpNB.setBorder(BorderFactory.createEmptyBorder(5, 10, 10, 10));
jpNB.add(cls);
jpNB.add(cle);
jpNB.add(back);
jpNB.add(mod);
jpNB.add(copy);
jpNB.add(num[7]);
jpNB.add(num[8]);
jpNB.add(num[9]);
jpNB.add(divide);
jpNB.add(sqrt);
jpNB.add(num[4]);
jpNB.add(num[5]);
jpNB.add(num[6]);
jpNB.add(multiply);
jpNB.add(square);
jpNB.add(num[1]);
jpNB.add(num[2]);
jpNB.add(num[3]);
jpNB.add(subtract);
jpNB.add(reci);
jpNB.add(num[0]);
jpNB.add(dot);
jpNB.add(sign);
jpNB.add(plus);
jpNB.add(enter);
add(jpNB,BorderLayout.CENTER);
}
void setKey(){
addKeyListener(new KeyListener(){
public void keyPressed(KeyEvent e){
char vk=e.getKeyChar();
switch(vk){
case '+': plus.doClick();break;
case '-': subtract.doClick();break;
case '*': multiply.doClick();break;
case '/': divide.doClick();break;
case '.': dot.doClick();break;
case '_': sign.doClick();break;
case KeyEvent.VK_EQUALS:
case KeyEvent.VK_ENTER: enter.doClick();break;
}
int vkc=e.getKeyCode();
switch(vkc){
case KeyEvent.VK_BACK_SPACE: back.doClick();break;
case KeyEvent.VK_ESCAPE: cls.doClick();break;
case KeyEvent.VK_C: if(e.isControlDown()) copy.doClick();break;
}
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
char vk=e.getKeyChar();
switch(vk){
case KeyEvent.VK_0: num[0].doClick();break;
case KeyEvent.VK_1: num[1].doClick();break;
case KeyEvent.VK_2: num[2].doClick();break;
case KeyEvent.VK_3: num[3].doClick();break;
case KeyEvent.VK_4: num[4].doClick();break;
case KeyEvent.VK_5: num[5].doClick();break;
case KeyEvent.VK_6: num[6].doClick();break;
case KeyEvent.VK_7: num[7].doClick();break;
case KeyEvent.VK_8: num[8].doClick();break;
case KeyEvent.VK_9: num[9].doClick();break;
}
}
});
}
void oprtInput(String bac){
for(int i=0;i<10;i++){
if(bac.equals(num[i].getText())){
if(isE) oprt=0;
if(buffer.equals("0")){
buffer=""+i;
}else{
buffer=buffer+i;
}
isV=false;
isE=false;
snum=new BigDecimal(buffer);
text.setText(buffer);
return;
}
}
if(bac.equals(dot.getText())){
if(isE) oprt=0;
if(!isF){
isF=true;
buffer=buffer+".";
snum=new BigDecimal(buffer);
isV=false;
isE=false;
}
text.setText(buffer);
}else if(bac.equals(sign.getText())){
if(!isV){
System.out.println("**");
if(isE) oprt=0;
if(buffer.equals("0")) return;
if(buffer.matches("-[-.0-9]+")){
buffer=buffer.substring(1);
}else{
buffer="-"+buffer;
}
isV=false;
isE=false;
snum=new BigDecimal(buffer);
text.setText(buffer);
}
}else if(bac.equals(back.getText())){
if(isV) return;
if(buffer.equals("0")) return;
if(buffer.endsWith(".")) isF=false;
if(buffer.matches("[-]{0,1}[0-9]{1}")) buffer="0";
else buffer=buffer.substring(0,buffer.length()-1);
snum=new BigDecimal(buffer);
text.setText(buffer);
}
}
void oprtBinary(String bac){
if(bac.equals(plus.getText())){
if(oprt==0) fnum=snum;
if(!isV) calc();
oprt=1;
snum=fnum;
buffer="0";
isF=false;
isV=true;
isE=false;
show(snum);
}else if(bac.equals(subtract.getText())){
if(oprt==0) fnum=snum;
if(!isV) calc();
oprt=2;
snum=fnum;
buffer="0";
isF=false;
isV=true;
isE=false;
show(snum);
}else if(bac.equals(multiply.getText())){
if(oprt==0) fnum=snum;
if(!isV) calc();
oprt=3;
snum=fnum;
buffer="0";
isF=false;
isV=true;
isE=false;
show(snum);
}else if(bac.equals(divide.getText())){
if(oprt==0) fnum=snum;
if(!isV){
if(!calc()) return;
}
oprt=4;
snum=fnum;
buffer="0";
isF=false;
isV=true;
isE=false;
show(snum);
}else if(bac.equals(mod.getText())){
if(oprt==0) fnum=snum;
if(!isV){
if(!calc()) return;
}
oprt=5;
snum=fnum;
buffer="0";
isF=false;
isV=true;
isE=false;
show(snum);
}
}
void oprtUnary(String bac){
if(bac.equals(sign.getText())){
if(isV){
if(isE){
snum=fnum.multiply(BigDecimal.valueOf(-1));
}else{
snum=snum.multiply(BigDecimal.valueOf(-1));
}
show(snum);
}
}else if(bac.equals(square.getText())){
BigDecimal tmp;
if(isE){
tmp=fnum; oprt=0;
}else{
tmp=snum; buffer="0";
isF=false;
}
snum=tmp.multiply(tmp);
isE=false;
isV=true;
show(snum);
}else if(bac.equals(reci.getText())){
BigDecimal tmp;
if(isE){
tmp=fnum; oprt=0;
}else{
tmp=snum; buffer="0";
isF=false;
}
try{
snum=BigDecimal.ONE.divide(tmp,180,RoundingMode.HALF_EVEN);
}catch(ArithmeticException ex){
init();
text.setText("Error!");
return;
}
isE=false;
isV=true;
show(snum);
}else if(bac.equals(sqrt.getText())){
BigDecimal tmp;
if(isE){
tmp=fnum; oprt=0;
}else{
tmp=snum; buffer="0";
isF=false;
}
if(tmp.compareTo(BigDecimal.ZERO)<0){
init();
text.setText("Error!");
return;
}
BigDecimal top,bot;
if(tmp.compareTo(BigDecimal.ONE)>0){
top=BigDecimal.ONE; bot=tmp;
}else{
top=tmp; bot=BigDecimal.ONE;
}
BigDecimal mid=tmp.divide(BigDecimal.valueOf(2),180,RoundingMode.HALF_EVEN);
while(bot.subtract(top).compareTo(new BigDecimal("1e-150"))>=0){
if((mid.multiply(mid)).compareTo(tmp)>=0){
bot=mid;
}else{
top=mid;
}
mid=(top.add(bot)).divide(BigDecimal.valueOf(2),180,RoundingMode.HALF_EVEN);
}
snum=mid;
isE=false;
isV=true;
show(snum);
}
}
void oprtMem(String bac){
if(bac.equals(ms.getText())){
isM.setText("M");
if(isE){
mem=fnum;
}else{
mem=snum;
}
}else if(bac.equals(mc.getText())){
isM.setText("");
}else if(bac.equals(mr.getText())){
if(isE) oprt=0;
if(isM.getText().equals("M")){
snum=mem;
buffer="0";
isV=true;
isF=false;
show(snum);
}
}else if(bac.equals(ma.getText())){
if(isM.getText().equals("M")){
if(isE){
mem=mem.add(fnum);
}else{
mem=mem.add(snum);
}
}
}
}
void oprtSys(String bac){
if(bac.equals(enter.getText())){
if(!calc()) return;
isF=false;
isV=true;
isE=true;
buffer="0";
show(fnum);
}else if(bac.equals(copy.getText())){
text.selectAll();
text.copy();
}else if(bac.equals(cls.getText())){
init();
show(snum);
}else if(bac.equals(cle.getText())){
isF=false;
snum=BigDecimal.ZERO;
buffer="0";
show(snum);
}
}
public void actionPerformed(ActionEvent e){
String bac=e.getActionCommand();
oprtInput(bac);
oprtBinary(bac);
oprtUnary(bac);
oprtMem(bac);
oprtSys(bac);
}
public static void main(String args[]){
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
JOptionPane.showMessageDialog(null,"System UI picked error!","UI Error!",JOptionPane.ERROR_MESSAGE);
}
JCalculator frame=new JCalculator();
frame.setTitle("JCalculator");
frame.setSize(400,240);
frame.setResizable(false);
frame.setVisible(true);
frame.requestFocus();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private JLabel isM;
private JTextField text;
private String buffer;
private int oprt;
private boolean isF,isV,isE;
private BigDecimal fnum,snum,mem;
private JButton[] num;
private JButton dot,sign,enter;
private JButton plus,subtract,multiply,divide,mod;
private JButton square,sqrt,reci;
private JButton cls,cle,back,copy;
private JButton ms,mc,mr,ma;
}