实验二-自下而上分析-实验报告

实验二语法分析－自下而上分析实验的目的利用vc++6.0生成调试递归下降分析程序，以便对任意输入的符号串进行分析。本次实验的目的主要是加深对递归下降分析法的理解。二、语法分析器按照c++语言的语法规则检查词法分析输出的记号流是否符合这些规则，并根据这些规则所体现出的语言中的各种语法结构的层次性。把规则写入到vc++6.0的文件中，可以生成树状的层次结构。三、实验环境vc++6.0四、分析结果五、源程序实现#include<stdio.h>#include<malloc.h>#include<string>structstack{stack*top;charvalue;};charpop(stack*pst){chare;if(pst->top==pst){printf("Thestackisnull.");return0;}else{e=pst->top->value;pst->top--;returne;}}voidpush(stack*pst,chare){pst->top++;pst->top->value=e;}voidprintstack(stack*pst){stack*printtemp=pst;while(printtemp<=(pst->top)){printf("%c",printtemp->value);printtemp++;}}voidprintstring(stack*pst){stack*printtemp=(pst->top);while(printtemp>=pst){printf("%c",printtemp->value);printtemp--;}}voidprintSLR(int&number,stack*status,stack*grammar,stack*string){printf("%d",number);printstack(status);printf("");printstack(grammar);printf("");printstring(string);printf("");number++;}intmain(){stack*string=(stack*)malloc(40);string->top=string;string->top->value='#';stack*status=(stack*)malloc(40);status->top=status;status->top->value='0';stack*grammar=(stack*)malloc(40);grammar->top=grammar;grammar->top->value='#';FILE*fp;fp=fopen("C:\\wj.txt","a+");charfilestring[10][20]={'\0'};charstr[10]={'\0'};intstringnumber=0;intnumber=0;while(!feof(fp)){fgets(filestring[stringnumber],23,fp);if(filestring[stringnumber][0]!='\n')stringnumber++;}for(inti=0;i<=(stringnumber-1);i++){for(intj=strlen(filestring[i])-3;j>=0;j--)if(filestring[i][j]!='\n')push(string,filestring[i][j]);printf("此次分析的字符串为：%s\n",filestring[i]);printf("步骤状态栈符号栈输入串ACTION\n");printSLR(number,status,grammar,string);printf("移进\n");while(string->top->value!='#'){charch=pop(string);if(ch=='i'){push(grammar,ch);if(status->top->value=='0'){push(status,'5');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(grammar);push(status,'3');push(grammar,'F');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(grammar);push(status,'2');push(grammar,'T');printSLR(number,status,grammar,string);printf("归约\n");if(string->top->value=='+'||string->top->value=='-'){pop(status);pop(grammar);push(status,'1');push(grammar,'E');printSLR(number,status,grammar,string);printf("移进\n");}}elseif(status->top->value=='6'){push(status,'5');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(grammar);push(status,'3');push(grammar,'F');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(grammar);push(status,'9');push(grammar,'T');printSLR(number,status,grammar,string);printf("归约\n");if(string->top->value=='+'||string->top->value=='-'){pop(status);pop(status);pop(grammar);pop(grammar);printSLR(number,status,grammar,string);printf("移进\n");}}elseif(status->top->value=='7'){push(status,'5');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(grammar);push(status,'(');push(status,'1');push(status,'0');push(status,')');push(grammar,'F');printSLR(number,status,grammar,string);printf("归约\n");pop(status);pop(status);pop(status);pop(status);pop(status);pop(grammar);pop(grammar);printSLR(number,status,grammar,string);printf("移进\n");if(string->top->value=='+'||string->top->value=='-'){pop(status);pop(grammar);push(status,'1');push(grammar,'E');printSLR(number,status,grammar,string);printf("移进\n");}}elseprintf("Thereissomethingwrongneari.");}elseif(ch=='+'||ch=='-'){if(status->top->value=='1'||status->top->value=='8')push(status,'6');elseprintf("Thereissomethingwrongnear+or-\n");push(grammar,ch);printSLR(number,status,grammar,string);printf("移进\n");}elseif(ch=='*'|