编译语言-中间代码生成.doc

实验四 中间代码生成一、 实验内容设计一个程序，该程序能够将形如 x = y op z 的简单赋值语句翻译为对应的四元式序列，其中 op 可为+、-、*、/等二元运算符。（可参考实验指导书P163 至 P164）。要求用JAVA语言编程。例如：若输入赋值语句 a = b + c,则输出如下四元式序列。二、 程序代码InToPost.JAVApackage zlf;import java.io.IOException;public class InToPost private Stack theStack; private String input; private String output = ; public InToPost(String in) input = in; int stackSize = input.length(); theStack = new Stack(stackSize); public String doTrans() for (int j = 0; j input.length(); j+) char ch = input.charAt(j); switch (ch) case +: case -: gotOper(ch, 1); break; case *: case /: gotOper(ch, 2); break; case (: theStack.push(ch); break; case ): gotParen(ch); break; default: output = output + ch; break; while (!theStack.isEmpty() output = output + theStack.pop(); / System.out.println(output); return output; public void gotOper(char opThis, int prec1) while (!theStack.isEmpty() char opTop = theStack.pop(); if (opTop = () theStack.push(opTop); break; else int prec2; if (opTop = + | opTop = -) prec2 = 1; else prec2 = 2; if (prec2 prec1) theStack.push(opTop); break; else output = output + opTop; theStack.push(opThis); public void gotParen(char ch) while (!theStack.isEmpty() char chx = theStack.pop(); if (chx = () break; else output = output + chx; class Stack private int maxSize; private char stackArray; private int top; public Stack(int max) maxSize = max; stackArray = new charmaxSize; top = -1; public void push(char j) stackArray+top = j; public char pop() return stackArraytop-; public char peek() return stackArraytop; public boolean isEmpty() return (top = -1); QuaternaryTypeOfAlgorithm.JAVApackage zlf;import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.util.Stack;public class QuaternaryTypeOfAlgorithm extends JFrameprivate static Stack number = new Stack();private int n = 1;private JButton jbt = new JButton(生成);private JTextArea jta = new JTextArea();private JTextField jtf = new JTextField(A=B+C*D+E,20);private boolean hasError = false;public QuaternaryTypeOfAlgorithm()JPanel p1 = new JPanel();p1.add(jtf);p1.add(jbt);add(p1,BorderLayout.NORTH);add(new JScrollPane(jta),BorderLayout.CENTER);jbt.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e)String equation = jtf.getText().trim();create(equation);number.clear();hasError = false;repaint(););public void create(String input)String output;InToPost theTrans = new InToPost(input);output = theTrans.doTrans(); tryfor(int i = 0 ; i output.length(); i+)String t = output.substring(i, i+1); if(t.equals(+) String n1 = number.pop(); String n2 = number.pop(); String n3 = T+n; n+; number.push(n3); jta.append(n-1+: (+,+n2+,+n1+,+n3+)+n); else if(t.equals(-) String n1 = number.pop(); String n3 = T+n; n+; number.push(n3); jta.append(n-1+: (-,+n1+,+ +,+n3+)+n); else if(t.equals(*) String n1 = number.pop(); String n2 = number.pop(); String n3 = T+n; n+; number.push(n3); jta.append(n-1+: (*,+n2+,+n1+,+n3+)+n); else if(t.equals(/) String n1 = number.pop(); String n2 = number.pop(); String n3 = T+n; n+; number.push(n3); jta.append(n-1+: (/,+n2+,+n1+,+n3+)+n); else if(t.matches(a-zA-Z0-9=) number.push(t); /System.out.println(number:+t); String last2 = number.pop();number.pop(); String last1 = number.pop(); n+; jta.append(n-1+: (=,+last2+, ,+last1+)+n+n+n);catch(Exception e)hasError = true;if(hasError|!number.empty()JOptionPane.showMessageDialog(null, 你输入的算式表达式有错！请重新输入); number.clear();public static void main(String args)QuaternaryTypeOfAlgorith