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package caofeng;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class Calculator implements ActionListener{
private String str = "";
private JTextArea jtf;
private JFrame frame;
private Container contentPane;
private String []names={"1","2","3","+","退格",
"4","5","6","-","刷新",
"7","8","9","*",".",
"0","(",")","/","="
};
private JButton []buttons=new JButton[20];
public Calculator(){ //构造方法
frame=new JFrame("Calculator"); //定义一个框架
contentPane=frame.getContentPane(); //获取内容格
JPanel jp1=new JPanel(); //定义一个面板
jtf=new JTextArea("",7,43);
jtf.setEditable(false);
jp1.add(jtf);
JPanel jp2=new JPanel();
jp2.setLayout(new GridLayout(4,5,5,5)); //设置布局管理器
this.fillJP2(jp2);
contentPane.add(jp1,BorderLayout.NORTH);
contentPane.add(jp2,BorderLayout.SOUTH);
frame.setSize(500,300);
frame.setVisible(true);
}
private void fillJP2(JPanel j){ //添加组件
for(int i=0;i<names.length;i++){
buttons[i]=new JButton(names[i]);
j.add(buttons[i]);
buttons[i].addActionListener(this);
}
}
private boolean isQiTa(String str) {
if (str.equals("刷新") || str.equals("退格"))
return true;
return false;
}
public void actionPerformed(ActionEvent e){ //事件处理
String strCommand = e.getActionCommand();
if (!isQiTa(strCommand)&&!strCommand.equals("=")) {
str += strCommand;
jtf.setText(str);
}
if (strCommand == "退格") {
if (str == "")
jtf.setText("到头了,你还退什么退啊");
else {
if (str.length() == 1){
str ="";
jtf.setText(str);
}
else {
str = str.substring(0, str.length() - 1);
jtf.setText(str);
}
}
} else if (strCommand == "刷新") {
str="";
jtf.setText(str);
}else if(strCommand.equals("=")){
str+="=";
/////////////////////////////////
float f=new DealwithString().dealwithString(str); //调用
/////////////////////////////////
str+=f;
jtf.setText(str);
}
}
public static void main(String args[]){
new Calculator();
}
}
package caofeng;
import java.util.LinkedList;
import java.util.Queue;
public class DealwithString {
private String num = "";
private String s = "";
private Queue<String> queue = new LinkedList<String>();
private boolean isNum(String str) {
if (str.equals("0") || str.equals("1") || str.equals("2")
|| str.equals("3") || str.equals("4") || str.equals("5")
|| str.equals("6") || str.equals("7") || str.equals("8")
|| str.equals("9") || str.equals("."))
return true;
else
return false;
}
private boolean isFuHao(String str) {
if (str.equals("+") || str.equals("-") || str.equals("*")
|| str.equals("/") || str.equals("(") || str.equals(")"))
return true;
else
return false;
}
public float dealwithString(String str) {
float f = 0;
for (int i = 0; i < str.length(); i++) {
s = str.charAt(i) + "";
if (s.equals("=")) {
if (!num.equals("") ) {
queue.add(num);
queue.add(s);
num = "";
}
else {
queue.add(s);
}
}
if (isNum(s)) {
num += s;
}
else if (isFuHao(s)) {
if (!num .equals("")) {
queue.add(num);
queue.add(s);
num = "";
} else
queue.add(s);
}
}
for(String s:queue)
System.out.print(s+" ");
System.out.println();
////////////调用////////////////////
JiSuan js=new JiSuan();
f=js.evaluateExpression(queue);
///////////////////////////
return f;
}
public static void main(String args[]) {
DealwithString ds = new DealwithString();
//ds.dealwithString("1.2+(12+3)/2=");
}
}
package caofeng;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
public class JiSuan {
private String precede(String s1,String s2){ //进行优先级判断
String s3="";
char c1=s1.charAt(0);
char c2=s2.charAt(0);
switch(c2){
case '+':
case '-':
if(c1=='('||c1=='=')
s3="<";
else
s3=">";
break;
case '*':
case '/':
if(c1=='*'||c1=='/'||c1==')')
s3=">";
else
s3="<";
break;
case '(':
if(c1==')')
s3="括号不匹配";
else
s3="<";
break;
case ')':
if(c1=='(')
s3="=";
else if(c1=='=')
s3="括号不匹配";
else
s3=">";
break;
case '=':
if(c1=='=')
s3="=";
else if(c1=='(')
s3="括号不匹配";
else
s3=">";
break;
}
return s3;
}
private boolean in(String s){ //判断s是否为六种运算符之一,是返回true,否则返回false
char c=s.charAt(0);
switch(c){
case '+':
case '-':
case '*':
case '/':
case '(':
case '=':
case ')':return true;
default: return false;
}
}
private float operate(float f1,String s,float f2){ //计算操作
char c=s.charAt(0);
switch(c){
case '+':return f1+f2;
case '-':return f1-f2;
case '*':return f1*f2;
default :return f1/f2;
}
}
public float evaluateExpression(Queue<String> queue){ //计算主体
for(String s:queue){
System.out.print(s+" ");
}
Stack<String> stackNUM=new Stack<String>(); //数字栈
Stack<String> stack2EXP=new Stack<String>(); //符号栈
stack2EXP.add("=");
String q=queue.poll(); //从队列头部取一个元素
String s1=stack2EXP.peek();//获取栈顶元素
while(!q.equals("=")||!s1.equals("=")){
if(in(q))
switch(precede(s1,q).charAt(0)){
case '<':stack2EXP.add(q);q=queue.poll();break;
case '=':stack2EXP.pop();q=queue.poll();break;
case '>':String stemp=stack2EXP.pop();float f2=Float.parseFloat(stackNUM.pop());
float f1=Float.parseFloat(stackNUM.pop());stackNUM.add(operate(f1,stemp,f2)+"");
break;
}
else{
stackNUM.add(q);
q=queue.poll();
}
s1=stack2EXP.peek();
}
return Float.parseFloat(stackNUM.pop());
}
public static void main(String args[]){ //测试方法
Queue<String> queue=new LinkedList<String>();
queue.add("1.2");
queue.add("+");
queue.add("(");
queue.add("2");
queue.add("+");
queue.add("3");
queue.add(")");
queue.add("/");
queue.add("2");
queue.add("=");
JiSuan js=new JiSuan();
System.out.println(js.evaluateExpression(queue));
}
}