編譯原理語義分析實(shí)驗(yàn)報告免費(fèi)

1、語義分析實(shí)驗(yàn)報告一、 實(shí)驗(yàn)?zāi)康模和ㄟ^上機(jī)實(shí)習(xí)，加深對語法制導(dǎo)翻譯原理的理解，掌握將語法分析所識別的語法成分變換為中間代碼的語義翻譯方法。二、 實(shí)驗(yàn)要求：采用遞歸下降語法制導(dǎo)翻譯法，對算術(shù)表達(dá)式、賦值語句進(jìn)行語義分析并生成四元式序列。三、 算法思想：1、設(shè)置語義過程。（1）emit(char *result,char *ag1,char *op,char *ag2)該函數(shù)的功能是生成一個三地址語句送到四元式表中。四元式表的結(jié)構(gòu)如下：structchar result8;char ag18;char op8;char ag28;quad20; (2) char *newtemp()該函數(shù)回送一個新

2、的臨時變量名，臨時變量名產(chǎn)生的順序?yàn)閠1，t2，char *newtemp(void)char *p; char m8; p=(char *)malloc(8); k+; itoa(k,m,10); strcpy(p+1,m); p0=t; return(p);2、函數(shù)lrparser 在原來語法分析的基礎(chǔ)上插入相應(yīng)的語義動作：將輸入串翻譯成四元式序列。在實(shí)驗(yàn)中我們只對表達(dá)式、賦值語句進(jìn)行翻譯。四、 源程序代碼：#include#include#include#includestructchar result12;char ag112;char op12;char ag212;quad;cha

3、r prog80,token12;char ch;int syn,p,m=0,n,sum=0,kk; /p是緩沖區(qū)prog的指針，m是token的指針char *rwtab6=begin,if,then,while,do,end;void scaner();char *factor(void);char *term(void);char *expression(void);int yucu();void emit(char *result,char *ag1,char *op,char *ag2);char *newtemp();int statement();int k=0;void emi

4、t(char *result,char *ag1,char *op,char *ag2)strcpy(quad.result,result);strcpy(quad.ag1,ag1); strcpy(quad.op,op);strcpy(quad.ag2,ag2); coutquad.result=quad.ag1quad.opquad.ag2endl;char *newtemp()char *p;char m12;p=(char *)malloc(12);k+;itoa(k,m,10);strcpy(p+1,m);p0=t;return (p);void scaner()for(n=0;n=

5、a&ch=a&ch=0&ch=a&ch=a&ch=z)tokenm+=ch;ch=progp+;tokenm+=0;p-;syn=10;for(n=0;n=0&ch=0&ch32767)syn=-1;else switch(ch)case)syn=21;tokenm+=ch;else if(ch=)syn=22;tokenm+=ch;elsesyn=23;p-;break;case:m=0;tokenm+=ch;ch=progp+;if(ch=)syn=24;tokenm+=ch;elsesyn=20;p-;break;case:m=0;tokenm+=ch;ch=progp+;if(ch=)

6、syn=18;tokenm+=ch;elsesyn=17;p-;break;case*:syn=13;token0=ch;break;case/:syn=14;token0=ch;break;case+:syn=15;token0=ch;break;case-:syn=16;token0=ch;break;case=:syn=25;token0=ch;break;case;:syn=26;token0=ch;break;case(:syn=27;token0=ch;break;case):syn=28;token0=ch;break;case#:syn=0;token0=ch;break;de

7、fault: syn=-1;break;int lrparser()/cout調(diào)用lrparserendl;int schain=0; kk=0; if(syn=1) scaner(); schain=yucu(); if(syn=6) scaner(); if(syn=0 & (kk=0) coutsuccess!endl; else if(kk!=1)cout缺end!endl;kk=1; else cout缺begin!endl;kk=1; return(schain);int yucu()/cout調(diào)用yucuendl;int schain=0; schain=statement();

8、 while(syn=26)scaner(); schain=statement(); return(schain);int statement()/cout調(diào)用statementendl;char *eplace,*tt; eplace=(char *)malloc(12); tt=(char *)malloc(12); int schain=0;switch(syn)case 10:strcpy(tt,token);scaner();if(syn=18)scaner();strcpy(eplace,expression();emit(tt,eplace,);schain=0;elsecou

9、t缺少賦值符!endl;kk=1;return(schain);break;return(schain);char *expression(void)char *tp,*ep2,*eplace,*tt;tp=(char *)malloc(12);ep2=(char *)malloc(12);eplace=(char *)malloc(12);tt =(char *)malloc(12);strcpy(eplace,term ();/調(diào)用term分析產(chǎn)生表達(dá)式計(jì)算的第一項(xiàng)eplacewhile(syn=15)|(syn=16)if(syn=15)strcpy(tt,+);else strcpy(

10、tt,-);scaner();strcpy(ep2,term();/調(diào)用term分析產(chǎn)生表達(dá)式計(jì)算的第二項(xiàng)ep2strcpy(tp,newtemp();/調(diào)用newtemp產(chǎn)生臨時變量tp存儲計(jì)算結(jié)果emit(tp,eplace,tt,ep2);/生成四元式送入四元式表strcpy(eplace,tp);return(eplace);char *term(void)/cout調(diào)用termendl;char *tp,*ep2,*eplace,*tt;tp=(char *)malloc(12);ep2=(char *)malloc(12);eplace=(char *)malloc(12);tt=

11、(char *)malloc(12);strcpy(eplace,factor();while(syn=13)|(syn=14)if(syn=13)strcpy(tt,*);else strcpy(tt,/);scaner();strcpy(ep2,factor();/調(diào)用factor分析產(chǎn)生表達(dá)式計(jì)算的第二項(xiàng)ep2strcpy(tp,newtemp();/調(diào)用newtemp產(chǎn)生臨時變量tp存儲計(jì)算結(jié)果emit(tp,eplace,tt,ep2);/生成四元式送入四元式表strcpy(eplace,tp);return(eplace); char *factor(void)char *fpla

12、ce;fplace=(char *)malloc(12);strcpy(fplace,);if(syn=10)strcpy(fplace,token);/將標(biāo)識符token的值賦給fplacescaner();else if(syn=11)itoa(sum,fplace,10);scaner();else if(syn=27)scaner();fplace=expression();/調(diào)用expression分析返回表達(dá)式的值if(syn=28)scaner();elsecout缺)錯誤!endl;kk=1;elsecout缺(錯誤!endl;kk=1;return(fplace);void main()p=0;cout*語義分析程序*endl;coutplease input string:endl;docin.get(ch);progp+=ch;while(ch!=#);p=0;scaner();lrparser();五、 結(jié)果驗(yàn)證：1、 給定源程序