编译LL1文法预测,编译原理课程设计

import java.util.*; import java.math.*; public class match { static String str1() { Scanner input=new Scanner(System.in); System.out.println("请输入要测试的字符串,回车结束。"); String s=input.next(); System.out.println("测试字符串为："+s); return s; } static void str1_Print(String s,int s1) { System.out.print(s.substring(s1)); System.out.print("\t\t"); } static void match(GraTest v,stackX w) { // Character s=v.num[1][0].charAt(0);//将起始附赋给s String strstr; strstr=str1();//分析串 // int sl=strstr.length()-1;//s1字符串长度 int s1=0; //比较栈顶符号与字符串值 int x1,a1; x1=0; w.StackX();//申请分配空间 w.push('#'); w.push('E');//'#''s'进栈 Character a=strstr.charAt(0);//当前终结符送a Character x=w.peek();//取栈顶符号给x int p=0;//p 为1 x为终结符,0 x为非终结符 int finish=0; while(finish==0){ x=w.peek(); a=strstr.charAt(s1); for(int t=0;t<v.num[0].length;t++) { Character b=v.num[0][t].charAt(0); if(x.equals(b)||x.equals('#')) p=1; } if(p==1)//x为终结符 { if(x==a){//x等于a if(!x.equals('#')) { w.stack_Print(); str1_Print(strstr,s1); System.out.println(a+"匹配"); w.pop();//弹出栈顶符号} s1++;//读入下一个符号 if(w.isEmpty()==1) { System.out.println("stack is null!"); break; } if(s1>strstr.length()-1) { w.stack_Print(); str1_Print(strstr,s1); System.out.println("string is null!"); break; } } else { w.stack_Print(); str1_Print(strstr,s1); System.out.println("OK"); finish=1; } p=0; } else { w.stack_Print(); str1_Print(strstr,s1); System.out.println("match error!");//结束程序 break; } } else//x为非终结符 { a1=v.getA(a);//列号 x1=v.getX(x);//行号 if(x1!=0 && a1!=0) { w.stack_Print(); str1_Print(strstr,s1); System.out.println(v.num[x1][a1]); if(v.num[x1][a1].charAt(0)=='N')//是否是空串 { w.pop(); } else { w.pop(); for(int l=v.num[x1][a1].length()-1;l>=0;l--) { w.push(v.num[x1][a1].charAt(l)); } } } else { w.stack_Print(); str1_Print(strstr,s1); System.out.println("无可用的推导式"); break; } } } } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub GraTest v=new GraTest(); v.arr_Init();//输入表格 v.array_P();//打印表格 stackX s=new stackX(); System.out.println(); System.out.print("分析栈\t\t"); System.out.print("剩余串\t\t"); System.out.println("产生式或提示"); match(v,s); } }