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学习计算机或者软件工程的人都知道编译原理是一门非常重要的课程，下面是本人学习编译原理过后写的词法分析的源码，喜欢的可以看看，顺便我附上一个下载地址：
地址一:
地址二:
####include #####include #####include #####include #####include #####include #####include using namespace std;class Content{private:int id;int forToken;string content;char character;char *token;char *characterSet;int c;string str;map store;public:string getStr();long getLength();int getC();void display();bool operator==(char rch);Content(string content);~Content();void stringToChar();char get_Char();bool getbe();void concatenation();bool letter();bool digit();int reserve();void retract();void buildList();string error();string analysis();};//bool Content::operator==(char rch){// char lch;// if(strcpy(&lch,&rch)==0){// return 1;// }// else// return 0;//}Content::Content(string _content){content=_content;c=0;id=0;character=' ';forToken=0;str="";characterSet=new char[content.length()+1];//最后又'\0'token=new char[100];}Content::~Content(){free(characterSet);free(token);delete []characterSet;delete []token;}void Content::stringToChar(){strcpy(characterSet,content.c_str());//返回的是const char*，也就是字符数组的首地址}/*www.panmama.com 转载请务必告知*/int Content::getC(){return c;}long Content::getLength(){return content.length();}char Content::get_Char(){character=characterSet[c];if(!(character==' ')||!(character!='\n')||!(character!='\t')){c++;}//非空符号，指针向后加1return character;}bool Content::getbe(){if(character==' '||character=='\n'||character=='\t'){c++;return 1;}return 0;}void Content::display(){for(int i=0; i ='0'&&character<='9')return true;return false;}bool Content::letter(){if((character>='a'&&character<='z')||(character>='A'&&character<='Z')){return true;}return false;}int Content::reserve(){// int i=0;// str="";// while(token[i]!=' ')// {// str+=token[i];// i++;// }str=getStr();if(str=="if"){return 4;}else if(str=="int"){return 1;}else if(str=="for"){return 6;}else if(str=="char"){return 3;}else if(str=="void"){return 12;}else if(str=="main"){return 2;}else if(str=="else"){return 5;}else if(str=="case"){return 9;}else if(str=="while"){return 7;}else if(str=="float"){return 11;}else if(str=="const"){return 12;}else if(str=="break"){return 13;}else if(str=="switch"){return 8;}else if(str=="return"){return 14;}else if(str=="switch"){return 8;}else if(str=="double"){return 15;}else if(str=="string"){return 16;}else if(str=="printf"){return 17;}else{return 0;}}void Content::retract(){c--;character=' ';}void Content::buildList(){//id=18;store.insert(pair (1,"int"));store.insert(pair (2,"main"));store.insert(pair (3,"char"));store.insert(pair (4,"if"));store.insert(pair (5,"else"));store.insert(pair (6,"for"));store.insert(pair (7,"while"));store.insert(pair (8,"switch"));store.insert(pair (9,"case"));store.insert(pair (11,"float"));store.insert(pair (12,"const"));store.insert(pair (13,"break"));store.insert(pair (14,"return"));store.insert(pair (15,"double"));store.insert(pair (16,"string"));store.insert(pair (17,"printf"));store.insert(pair (id,str));// if(id!=20)// id++;// else// id=21;}string Content::error(){return "有误";}string Content::analysis(){char s;string num;int k;for(int i=0; i<100; i++){token[i]=' ';}s=get_Char();//从数组中取一个字符if(getbe())//是空格return "";//是空格返回“”switch(s){case 'a':case 'b':case 'c':case 'd':case 'e':case 'f':case 'g':case 'h':case 'i':case 'j':case 'k':case 'l':case 'm':case 'n':case 'o':case 'p':case 'q':case 'r':case 's':case 't':case 'u':case 'v':case 'w':case 'x':case 'y':case 'z':while(letter()||digit()){concatenation();get_Char();}forToken=0;k=reserve();if(k==0){buildList();return "(10,ID)";}else{buildList();stringstream ss;string first;string second;ss< ::iterator iter;for(iter=store.begin(); iter!=store.end(); iter++){if(iter->first==k)second=iter->second;}return "("+first+","+second+")";}break;case '0':case '1':case '2':case '3':case '4':case '5':case '6':case '7':case '8':case '9':while(digit()){concatenation();get_Char();}retract();//budlist();对其登记num=getStr();return "("+num+",NUM)";break;case'+':return "(22,+)";break;case'-':return "(23,-)";break;case'*':return "(24,*)";break;case'/':return "(25,/)";break;case'(':return "(26,()";break;case')':return "(27,))";break;case'[':return "(28,[)";break;case']':return "(29,])";break;case'{':return "(30,{)";break;case'}':return "(31,})";break;case'"':return "(41,\")";break;case',':return "(32,,)";break;case':':return "(33,:)";break;case';':return "(34,;)";break;case'<':get_Char();if(character=='='){return "(38,<=)";}else{retract();return "(36,<)";}break;case'>':get_Char();if(character=='='){return "(37,>=)";}else{retract();return "(35,>)";}break;case'=':get_Char();if(character=='='){return "(39,==)";}else{retract();return "(21,=)";}break;case'!':get_Char();if(character=='='){return "(40,!=)";}else{retract();}break;case '\0':return "1000";break;default:error();}}int main(){string temp="int main(){int c=33;if(c=33){printf();}}";Content b=(temp);b.stringToChar();//c.display();while(b.getC()
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