java 计算器

突然想到了小学的时候使用的简单计算器 ,而且刚刚做了nyoj35 表达式求值这道题 

就想着用java实现一下。

main函数

package calculator;

public class Main {
  public static void main(String args[]){
    new Fram();
  }
}

界面+事件：

package calculator;
import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
public class Fram extends JFrame implements ActionListener{
  JTextField show;
  JButton button[];
  JPanel panel;
  Cal_str cal;
  boolean flag=false;
  int x=-60,y=0;
  String anniu1[]={"(",")","清除","退格"};
  String anniu2="789/456*123-.0=+";
  Fram(){
    button=new JButton[26];
    panel=new JPanel();
    panel.setLayout(null);
    for(int i=0;i<20;i++){
      if(i==4||i==8||i==12||i==16){
        x=-60;
        y+=35;
      }
      if(i<4){
        button[i]=new JButton(anniu1[i]);
        button[i].setBounds(x+=62,y,60,35);
      }
      else{
        char ch=anniu2.charAt(i-4);
        button[i]=new JButton(String.valueOf(ch));
        button[i].setBounds(x+=62,y,60,35);
      }
      button[i].addActionListener(this);
      panel.add(button[i]);
    }
    add(panel,BorderLayout.CENTER);
    show=new JTextField(5);
    add(new JScrollPane(show),BorderLayout.NORTH);
    setResizable(false);
    setVisible(true);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(340,270,256,230);
    setTitle("计算器");
  }
  @Override
  public void actionPerformed(ActionEvent e) {
    // TODO Auto-generated method stub
    JButton anniu=(JButton)e.getSource();
    if(flag){
      show.setText(null);
      flag=false;
    }
    if(anniu.getLabel().equals("=")){
      show.setText(show.getText()+anniu.getLabel());
      char []str=show.getText().toCharArray();
      cal=new Cal_str(str,show);
      flag=true;
    }
    else if(anniu.getLabel().equals("清除")){
      show.setText(null);
      
    }
    else if(anniu.getLabel().equals("退格")){
      char []str=show.getText().toCharArray();
      if(str.length>0)
      show.setText(new String(str,0,str.length-1));
    }
    else{
      show.setText(show.getText()+anniu.getLabel());
    }
    
    
  }
}

计算：

package calculator;
import java.util.*;
import java.awt.*;
import javax.swing.*;
public class  Cal_str{
  Cal_str(char[] str,JTextField show){
  char []temp = new char[100];
  Stack<Character> optr=new Stack<Character>();
  Stack<Double> opnd=new Stack<Double>();
  int k=0,test=-1,count=0;
  optr.clear();
  opnd.clear();
  optr.add('=');
  try{
    
    for(int i=0;i<str.length;){
      test=i;
      if(i==test)
        count++;
      if(count>=20){
        break;
      }
      if(Character.isDigit(str[i])||str[i]=='.'){
        temp[k++]=str[i];
        i++;
        continue;
      }
      if(k!=0){
        opnd.add(Double.parseDouble(new String(temp,0,k)));
        k=0;
      }
      switch(compare(optr.peek(),str[i])){
      case 60:
        optr.add(str[i]);i++;break;
      case 61:
        optr.pop();i++;break;
      case 62:
        opnd.add(result(opnd.pop(),opnd.pop(),optr.pop()));
        break;
      }
    }
    if(count<20)
    show.setText(opnd.pop().toString());
    else
      JOptionPane.showMessageDialog(show, "输入错误，请重新输入！");
  }
  catch(Exception e){
    JOptionPane.showMessageDialog(show, "输入错误，请重新输入！");
  }
}
private static Double result(Double num1, Double num2, char ch) {//计算
  // TODO Auto-generated method stub
  if(ch=='+')
    return num2+num1;
  if(ch=='-')
    return num2-num1;
  if(ch=='*')
    return num2*num1;
  if(ch=='/')
    return num2/num1;
  return null;
}
private static int compare(char ch1,char ch2){//返回运算符间关系
  String oper[]={">><<<>>",">><<<>>",">>>><>>",
      ">>>><>>","<<<<<= ",">>>> >>","<<<<< ="};
  int x,y;
  x=to_num(ch1);
  y=to_num(ch2);
  return (int)(oper[x].charAt(y));  
}
private static int to_num(char ch) {
  if(ch=='+')
    return 0;
  else if(ch=='-')
    return 1;
  else if(ch=='*')
    return 2;
  else if(ch=='/')
    return 3;
  else if(ch=='(')
    return 4;
  else if(ch==')')
    return 5;
  else if(ch=='=')
  return 6;
  else 
    return -1;
}
}

刚刚又优化了一下 在计算时候如果循环20次不运行就会判错。

已经在nyoj35AC请放心。。