實(shí)驗(yàn)1-3-《編譯原理》詞法分析程序設(shè)計(jì)方案

實(shí)驗(yàn)1-3《編譯原理》S語言詞法分析程序設(shè)計(jì)方案一、實(shí)驗(yàn)?zāi)康牧私庠~法分析程序的兩種設(shè)計(jì)方法之一：根據(jù)狀態(tài)轉(zhuǎn)換圖直接編程的方式；二、實(shí)驗(yàn)內(nèi)容 1．根據(jù)狀態(tài)轉(zhuǎn)換圖直接編程編寫一個(gè)詞法分析程序，它從左到右逐個(gè)字符的對(duì)源程序進(jìn)行掃描，產(chǎn)生一個(gè)個(gè)的單詞的二元式，形成二元式（記號(hào)）流文件輸出。在此，詞法分析程序作為單獨(dú)的一遍，如下圖所示。具體任務(wù)有：（1）組織源程序的輸入（2）拼出單詞并查找其類別編號(hào)，形成二元式輸出，得到單詞流文件（3）刪除注釋、空格和無用符號(hào)（4）發(fā)現(xiàn)并定位詞法錯(cuò)誤，需要輸出錯(cuò)誤的位置在源程序中的第幾行。將錯(cuò)誤信息輸出到屏幕上。（5）對(duì)于普通標(biāo)識(shí)符和常量，分別建立標(biāo)識(shí)符表和常量表（使用線性表存儲(chǔ)），當(dāng)遇到一個(gè)標(biāo)識(shí)符或常量時(shí)，查找標(biāo)識(shí)符表或常量表，若存在，則返回位置，否則返回0并且填寫符號(hào)表或常量表。標(biāo)識(shí)符表結(jié)構(gòu)：變量名，類型（整型、實(shí)型、字符型），分配的數(shù)據(jù)區(qū)地址注：詞法分析階段只填寫變量名，其它部分在語法分析、語義分析、代碼生成等階段逐步填入。常量表結(jié)構(gòu)：常量名，常量值三、實(shí)驗(yàn)要求1．能對(duì)任何S語言源程序進(jìn)行分析 在運(yùn)行詞法分析程序時(shí)，應(yīng)該用問答形式輸入要被分析的S源語言程序的文件名，然后對(duì)該程序完成詞法分析任務(wù)。2．能檢查并處理某些詞法分析錯(cuò)誤詞法分析程序能給出的錯(cuò)誤信息包括：總的出錯(cuò)個(gè)數(shù)，每個(gè)錯(cuò)誤所在的行號(hào)，錯(cuò)誤的編號(hào)及錯(cuò)誤信息。 本實(shí)驗(yàn)要求處理以下兩種錯(cuò)誤（編號(hào)分別為1，2）： 1：非法字符：單詞表中不存在的字符處理為非法字符，處理方式是刪除該字符，給出錯(cuò)誤信息，“某某字符非法”。 2：源程序文件結(jié)束而注釋未結(jié)束。注釋格式為：/*……*/四、保留字和特殊符號(hào)表單詞代碼123456789單詞intcharfloatvoidconstforifelsethen單詞助記符intcharfloatvoidconstforifelsethen內(nèi)碼值單詞代碼101112131415161718單詞whileswitchbreakbeginend標(biāo)識(shí)符數(shù)字（包括整數(shù)和實(shí)數(shù)）單詞助記符whileswitchbreakbeginendidnum內(nèi)碼值在符號(hào)表中的位置在常數(shù)表中的位置單詞代碼192021222324252627單詞+-*/%()[]單詞助記符+-*/%()[]內(nèi)碼值單詞代碼28282930單詞!=<><=>===；{}單詞助記符rlop；{}內(nèi)碼值!=<><=>===--單詞代碼373839404142434445單詞/=+=-=*=%=||&&!=單詞助記符/=+=-=*=%=orandnot=內(nèi)碼值單詞的構(gòu)詞規(guī)則：字母=[A-Za-z]數(shù)字=[0-9]標(biāo)識(shí)符=（字母|_）（字母|數(shù)字）*數(shù)字=數(shù)字(數(shù)字)*(.數(shù)字+|)四、S語言表達(dá)式和語句說明 1．算術(shù)表達(dá)式:+、-、*、/、% 2．關(guān)系運(yùn)算符：>、>=、<、<=、==、！= 3．賦值運(yùn)算符：=，+=、-=、*=、/=、%= 4．變量說明：類型標(biāo)識(shí)符變量名表； 5．類型標(biāo)識(shí)符：intcharfloat 6．If語句：if表達(dá)式then語句[else語句] 7．For語句：for（表達(dá)式1；表達(dá)式2；表達(dá)式3）語句 8．While語句：while表達(dá)式do語句 9．S語言程序：由函數(shù)構(gòu)成，函數(shù)不能嵌套定義。函數(shù)格式為：返回值函數(shù)名（參數(shù)）{數(shù)據(jù)說明Key_wordKey[MAXSIZE]={{"int","int","-"},{"char","char","-"},{"float","float","-"}, {"void","void","-"},{"const","const","-"},{"for","for","-"}, {"if","if","-"},{"else","else","-"},{"then","then","-"}, {"while","while","-"},{"switch","switch","-"},{"break","break","-"}, {"begin","begin","-"},{"end","end","-"},{"","",""}, {"","",""},{"","id",""},{"","num",""}, {"+","+","-"},{"-","-","-"},{"*","*","-"}, {"/","/","-"},{"%","%","-"},{"(","(","-"}, {")",")","-"},{"[","[","-"},{"]","]","-"}, {"","",""},{"<","rlop","<"},{">","rlop",">"}, {"<=","rlop","<="},{">=","rlop",">="},{"=","rlop","="}, {"!=","rlop","!="},{";",";","-"},{"","",""}, {"/=","/=","-"},{"+=","+=","-"},{"-=","-=","-"}, {"*=","*=","-"},{"%=","%=","-"},{"||","or","-"}, {"&&","and","-"},{"!","not","-"},{"=","=","-"}};//打開關(guān)閉文件intInitscanner(){ printf("請(qǐng)輸入要輸入的文件:\n"); scanf("%s",infile); if((in=fopen(infile,"r"))==NULL) { printf("cannotopeninfile!\n"); return0; } if((out=fopen("word.txt","a+"))==NULL) { printf("cannotopenoutfile!\n"); return0; } return0;}//寫入文件voidOutput(intn,intm){ fputs("(",out); fputs(Key[n].keySign,out); fputs(",",out); if(m==-1) fputs(Key[n].keyValue,out); else fputs(lownum[m],out);//下標(biāo) fputs(")",out);}//Isalpha函數(shù)：識(shí)別保留字和標(biāo)識(shí)符intIsalpha(){ inti; for(i=0;i<16;i++)//關(guān)鍵字 { if(strcmp(token,Key[i].keyWord)==0) { Output(i,-1); return0; } } //標(biāo)識(shí)符Word[NUM][MAX] for(i=0;i<NUM;i++) { if((Word[i][0]!=NULL)&&strcmp(token,Word[i])==0) { Output(16,i); return0; } if(Word[i][0]==NULL) { strcpy(Word[i],token); Output(16,i); return0; } } return0;}intIsnumber()//Isnumber函數(shù):consts[NUM][MAX]{ inti; for(i=0;i<NUM;i++) { if((consts[i][0]!=NULL)&&strcmp(token,consts[i])==0) { Output(17,i); return0; } if(consts[i][0]==NULL) { strcpy(consts[i],token); Output(17,i); return0; } } return0;}voidremove()//掃描指針回退一個(gè)字符{fseek(in,-1,SEEK_CUR);}//Isanotation函數(shù)：處理除號(hào)/和注釋voidIsanotation()//提示第一個(gè)字符已經(jīng)存為/了{(lán) charch,pre; ch=getc(in); if(ch=='=')//"/=" Output(36,-1); elseif(ch=='*')//"/*" { ch=getc(in); do{ if(feof(in)) { num++; printf("\n第(%d)行:注釋錯(cuò)誤:/*后面的字符全部當(dāng)做注釋，缺少結(jié)束注釋*/\n",n); break; } pre=ch; ch=getc(in); }while(pre!='*'||ch!='/'); } else//"/" { remove();//指針回退一個(gè)字符 Output(21,-1); }}//Isother函數(shù)識(shí)別其他特殊字符voidIsother(){ inti=1;intj=0; charch; if(token[0]=='<'||token[0]=='>'||token[0]=='!'||token[0]=='%'){ ch=getc(in); if(ch=='=') token[i++]=ch; elseremove(); }else if(token[0]=='|') { ch=getc(in); if(ch=='|') token[i++]=ch; else remove(); }else if(token[0]=='&') { ch=getc(in); if(ch=='&') token[i++]=ch; else remove(); } token[i]='\0'; for(i=18;i<45;i++) { if(strcmp(token,Key[i].keyWord)==0) { Output(i,-1); break; } } if(i==45) { num++; printf("\n第(%d)行:字符錯(cuò)誤:%s字符非法\n",n,token); }}voidScanner(){ charch; inti; ch=getc(in); while(!feof(in)) { while(ch==''||ch=='\t'||ch=='\n')//先統(tǒng)計(jì)行數(shù) { if(ch=='\n') ++n; ch=getc(in); } if(((ch>='a')&&(ch<='z'))||(ch=='_'))//標(biāo)識(shí)符isalpha(ch)單詞 { i=1; token[0]=ch; ch=getc(in); while(((ch>='a')&&(ch<='z'))||((ch>='0')&&(ch<='9')))//wordnumber { token[i++]=ch; ch=getc(in); } token[i]='\0'; Isalpha(); } elseif((ch>='0')&&(ch<='9'))//整數(shù) { i=1; token[0]=ch; ch=getc(in); while(isdigit(ch)) { token[i++]=ch; ch=getc(in); } token[i]='\0'; Isnumber(); } elseif(ch=='/')//區(qū)分"/","/=","/*" { token[0]=ch; Isanotation(); ch=getc(in); } else//特殊字符 { token[0]=ch;Isother(); ch=getc(in); } }}voidshow(){ inti; charch; printf("\n二元式:\n"); rewind(out); while(!feof(out)) { printf("%c",getc(out)); } printf("\n標(biāo)志符表\n"); for(i=0;i<NUM;i++) { if(Word[i][0]!=NULL) printf("%d,%s\n",i,Word[i]); } printf("\n常數(shù)表\n"); for(i=0;i<NUM;i++) { if(consts[i][0]!=NULL) printf("%d,%s\n",i,consts[i]); }}voidmain(){ Initscanner(); Scanner(); printf("\n共有%d個(gè)錯(cuò)誤\n",num); show(); fclose(in); fclose(out);}九、實(shí)驗(yàn)結(jié)果輸入文件voidaa()beginfloatrate,circle;rate=3;circle=3.