词法分析（C++)

/**词法分析.cpp*@author liuxiaochun**/#include<iostream>#include<string.h>using namespace std;#define MaxSize 1000char LetterProcess(char ch); //以字母开头的串处理char NumberProcess(char ch); //以数字开头的串的处理char OtherProcess(char ch); //其它字符串的处理void isKeyWord(char letter[]); //判断是关键字还是标识符char *KeyWord[65] ={"include","auto","const","double","float","int","short","struct","unsigned","enum", "break","continue","else","for","long","signed","switch","void","case","default", "goto","register","sizeof","typedef","volatile","char","do","extern","if","return", "static","union","while","asm","dynamic_cast","bool","explicit","new","static_cast","typeid","catch","false","operator","template","typename","class","friend","private","this","using","const_cast", "inline","public","throw","virtual","delete","mutable","protected","true","wchar_t", "namespace","reinterpret_cast","try","cin","cout"};int isAlpha(char c); //字母int isDigital(char c); //数字int isSpace(char c); //空格int is_char(char c); //下划线int isNumber(char c); //判断数符串后的下一符号 若为以下则返回1用以判断该串是否为数值FILE *f = fopen("test.cpp","r"); //打开需要扫描的源文件int main(){char str[200];int choose; char c;while(true){cout<<"请选择需要分析的源文件：1，程序内置源文件；2，输入文件的路径"<<endl;cin>>choose;if(choose==2){cout<<"请输入文件路径:";scanf("%s",&str);f=fopen(str,"r");}if(f==NULL){cout<<"Can't open file!"<<endl;break;}else{c =fgetc(f); //读取第一个字符while(c!=EOF){if(isAlpha(c)) c = LetterProcess(c); elseif(isDigital(c))c = NumberProcess(c);elsec =OtherProcess(c);}}getchar();fclose(f);}return 0;}int isAlpha(char c) //是否字母{if( ('a'<= c && c<='z')||('A'<=c && c<='Z'))return 1;elsereturn 0;}int isDigital(char c) //是否数字{if('0'<=c && c<='9')return 1;elsereturn 0;}int isSpace(char c) //是否空格{if( c==' ')return 1;elsereturn 0;}int is_char(char c) //下划线{if(c=='_')return 1;elsereturn 0;}int isNumber(char c) //判断数符串后的下一符号 若为以下则返回1{switch(c){case ' ':case '>':case ',':case ';':case '/':case '*':case '+':case '-':case ']':case '<':case '=':case ')':case '/n':return 1;default:return 0;}}char LetterProcess(char ch) //以字母开头的串处理{int i =-1;char LetterTemp[MaxSize];memset(LetterTemp, 0x00, sizeof(LetterTemp));while(isAlpha(ch)||isDigital(ch)||is_char(ch)) //是字母、数字、下划线{LetterTemp[++i] = ch;ch = fgetc(f);}if(ch=='.') //头文件标识符处理{LetterTemp[++i]=ch;ch = fgetc(f);if(ch=='h'){LetterTemp[++i]= ch;LetterTemp[i+1]='/0';cout<<LetterTemp<<"/t/t头文件名"<<endl;ch = fgetc(f);}}else{LetterTemp[i+1] = '/0';isKeyWord(LetterTemp); //判断是关键字还是标识符}return ch;}void isKeyWord(char letter[]) //判断是否关键字{int mark = 0;for(int i = 0; i<63; i++){if(strcmp(letter,KeyWord[i]) == 0) //对比{mark = 1;break;}}if(mark==1)cout<<letter<<"/t/t关键字"<<endl;elsecout<<letter<<"/t/t标识符"<<endl;}//数值处理char NumberProcess(char ch){int i = -1; char NumberTemp[MaxSize];memset(NumberTemp, 0x00, sizeof(NumberTemp));while(isDigital(ch)||ch=='.') //数符处理{NumberTemp[++i] = ch;ch = fgetc(f);}if(isNumber(ch)==1) //检查数符串的下一位以判定该串是否表示数值{NumberTemp[i+1] = '/0';cout<<NumberTemp<<"/t/t数值"<<endl;return ch;}else{while(isSpace(ch)==0) //不是空格为字符串或者其他{NumberTemp[++i] = ch;ch = fgetc(f);}NumberTemp[i+1] = '/0';cout<<NumberTemp<<"/t/t非法标准符"<<endl;}return ch;}//特殊符号 注释 运算符处理char OtherProcess(char ch) //特殊符号 空格 换行等处理{int i = -1;char OtherTemp[MaxSize];if(isSpace(ch)==1) //都是空格处理{while(isSpace(ch)){ch = fgetc(f);}return ch;}else{if(ch=='/n'||ch=='/t') //换行处理 制表符tab处理{while(ch=='/n'||ch=='/t'){ch = fgetc(f);}return ch;}else {char temp;switch(ch){//特殊符号的处理case ',':case ';':case '#':case '{':case '}':case '[':case ']':case '(':case ')':case ':':case '.':cout<<ch<<"/t/t特殊符号"<<endl;ch = fgetc(f);return ch;break;case '>':memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch == '>') //'>'与'>>'处理{OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t特殊符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t特殊符号"<<endl;return ch;break;case '<': //'<'与'<<'处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch == '<') {OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t特殊符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t特殊符号"<<endl;return ch;break;//以下就运算符号与注释符号的处理case '-': //'-'、'--'与'-='处理 ->memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='-'||ch=='='||ch=='>'){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t特殊符号"<<endl;return ch;break;case '+': //'-'、'--'与'-='处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='+'||ch=='='){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;case '=': //'-'、'--'与'-='处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='='){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;case '&': //'&'、'&&'符号处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='&'){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;case '*': //'-'、'--'与'-='处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='='){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;case '|': //'||'运算符处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='|'){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}return ch;break;case '!': //'!'非运算符处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='='){OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;case '/': //'/'、'/='运算与'/*'、'//'处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符if(ch=='='||ch=='/'||ch=='*'){switch(ch){case '=':OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t运算符号"<<endl;ch = fgetc(f);break;case '/':OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';while(ch!='/n'){ch = fgetc(f);}cout<<OtherTemp<<"/t/t注释符号(该符号所在的行后面的内容都是注释)"<<endl;ch=fgetc(f);break;case '*':OtherTemp[++i]=ch;OtherTemp[i+1] = '/0';ch=fgetc(f);while(ch!='*'){ch = fgetc(f);}ch = fgetc(f);if(ch=='/')cout<<OtherTemp<<"/t/t注释符号('/*'与'*/'之间内容都是注释)"<<endl;ch=fgetc(f);break;}}elsecout<<temp<<"/t/t运算符号"<<endl;return ch;break;//串的处理"词法分析";case '"': //串" "处理memset(OtherTemp, 0x00, sizeof(OtherTemp));i = -1;temp = ch;OtherTemp[++i]=ch;ch = fgetc(f); //取下一个字符OtherTemp[++i]=ch;while(ch!='"'){ch = fgetc(f);OtherTemp[++i]=ch;}OtherTemp[i+1] = '/0';cout<<OtherTemp<<"/t/t串"<<endl;ch = fgetc(f);return ch;break;}}}return ch;}