编译原理算符优先分析算法.doc

,由于时间关系,尚未实现用程序计算FIRSTVT,LASTVT,因此本实验的各种非终结符及其之间的优先关系人为初始化。。+*id()#+><<<>>*>><<>>id>>>>(<<<<=)>>>>#<<<<=#include<>#include<>#include<>#defineMAX50//定义最大长度为50,可以变化structsst{chars[MAX];intps;//栈顶终结符指针inttop;//栈顶指针};structinputst{charin[MAX];intpin;//当前字符指针};//定义算符及其优先关系表charch[6]={'+','*','i','(',')','#'};charchrelation[6][6]={'>','<','<','<','>','>','>','>','<','<','>','>','>','>','@','@','>','>','<','<','<','<','=','@','>','>','@','@','>','>','<','<','<','<','@','=',};charrela(charc1,charc2){inti=0,j=0;while(ch[i]!=c1)i++;while(ch[j]!=c2)j++;returnchrelation[i][j];}intis_VN(charc1){//判断是否为非终结符inti=0;while(i<6){if(ch[i]==c1)return0;i++;}return1;}voidmain(){structsstS;for(inti=0;i<MAX;i++){[i]='';}[0]='#';=0;=0;structinputstinput;printf("请输入需分析的字符串,以#结尾,最大长度为%d:\n",MAX);scanf("%s",);printf("%s\n",);=0;printf("s栈优先关系当前符号输入流动作\n");intcursor;while(1){if(rela([],[])=='<'||rela([],[])=='='){for(cursor=0;cursor<=;cursor++)printf("%c",[cursor]);printf("%c",rela([],[]));printf("%c",[]);printf("");for(cursor=+1;cursor<strlen();cursor++)printf("%c",[cursor]);if([]=='#'&&[]=='N'&&rela([],[