简易编译器，具备词法分析、语法分析、语义分析功能，最后生成四元式.zip

#include <iostream> #include <cstring> #include <cstdlib> using namespace std; const int MAX = 1000; const int MAXOFIDENTIFIER = 25; const int KEYWORDNUM = 6; const int UNARYOPERATORNUM = 7; const int BINOCULAROPERATORNUM = 4; const int DELIMETERNUM = 7; bool errorFlag = false; enum ErrorType { LENGTHERROROFIDENTIFIER = 1, POINTERROR, LENGTHERROROFCONSTANT, UNKNOWNIDENTIFIER }; enum IDType { KEYWORD = 1, IDENTIFIER, INTEGER, FLOAT, UOPERATOR, BOPERATOR, DELIMETER, OTHER }; struct TableNode { int type; //标识符的类型 int line; //标识符所在行数 char token[MAXOFIDENTIFIER]; //标识符 }; TableNode tokenTable[MAX]; int tableNum = 0; const char* const keyWords[KEYWORDNUM] = {"begin", "else", "end", "if", "then","while"}; const char unaryOperators[] = {'+','-','*','/','=','<','>'}; const char* const binocularOperators[] = {"<=",">=",":=","<>"}; const char delimeters[] = {'(', ')' , ',' , ';' , '[' , ']' , '"'}; char* Express(int& tableIndex); //errorTYpe=1 变量长度错误 //errorType=2 小数点错误 //errorTYpe=3 常量长度错误 void Error(ErrorType errorType,int line,const char* str) { errorFlag = true; cout << "Error" << endl; switch (errorType) { case LENGTHERROROFIDENTIFIER: cout << "第" << line <<"行" << str << " 变量的长度超过限制！\n"; break; case POINTERROR: cout << "第" << line <<"行" << str << " 小数点错误！\n"; break; case LENGTHERROROFCONSTANT: cout << "第" << line <<"行" << str << " 常量的长度超过限制！\n"; break; case UNKNOWNIDENTIFIER: cout << "第" << line << "行" << str << "未知字符！\n"; } } void Scanner(const char* sourceCode) { int codeLength = strlen(sourceCode); int chIndex = 0; int line = 1; int tableIndex = 0; while (chIndex < codeLength) { //处理空格和Tab while (chIndex < codeLength && (sourceCode[chIndex] == ' ' || sourceCode[chIndex] == '\t')) chIndex++; if (chIndex >= codeLength) break; while (chIndex < codeLength && sourceCode[chIndex] == '\n') { line++; chIndex++; } if (chIndex >= codeLength) break; //标识符 if (isalpha(sourceCode[chIndex]) || sourceCode[chIndex] == '_') { char str[100]; int strLen = 0; str[strLen] = sourceCode[chIndex]; strLen++; chIndex++; while (chIndex<codeLength && (isalnum(sourceCode[chIndex]) || sourceCode[chIndex] == '_')) { str[strLen] = sourceCode[chIndex]; strLen++; chIndex++; } if (chIndex >= codeLength) break; str[strLen] = 0; if (strLen > MAXOFIDENTIFIER) Error(LENGTHERROROFIDENTIFIER,line,str); else { int i; for (i = 0;i < KEYWORDNUM;i++) if (strcmp(str,keyWords[i]) == 0) { tokenTable[tableIndex].type = KEYWORD; tokenTable[tableIndex].line = line; strcpy(tokenTable[tableIndex].token,str); tableIndex++; break; } if (i >= KEYWORDNUM) { tokenTable[tableIndex].type = IDENTIFIER; tokenTable[tableIndex].line = line; strcpy(tokenTable[tableIndex].token,str); tableIndex++; } } } //常数 else if (isdigit(sourceCode[chIndex])) { char str[100]; int strLen = 0; int pointFlag = 0;//0表示整数，1表示小数，2表示错误 str[strLen++] = sourceCode[chIndex++]; while (chIndex < codeLength && (isdigit(sourceCode[chIndex]) || sourceCode[chIndex] == '.')) { if (sourceCode[chIndex] == '.') pointFlag++; str[strLen++] = sourceCode[chIndex]; chIndex++; } if (chIndex >= codeLength) break; str[strLen] = 0; if (strLen > 20) Error(LENGTHERROROFCONSTANT,line,str); if (pointFlag > 1) Error(POINTERROR,line,str); else { tokenTable[tableIndex].line = line; strcpy(tokenTable[tableIndex].token,str); if (pointFlag == 0) tokenTable[tableIndex].type = INTEGER; else tokenTable[tableIndex].type = FLOAT; tableIndex++; } } //操作符、界符。未知字符 else { char str[3]; str[0] = sourceCode[chIndex]; str[1] = sourceCode[chIndex+1]; str[2] = 0; int i; for (i = 0;i < BINOCULAROPERATORNUM;i++) if (strcmp(str,binocularOperators[i]) == 0) { tokenTable[tableIndex].line = line; tokenTable[tableIndex].type = BOPERATOR; strcpy(tokenTable[tableIndex].token,str); tableIndex++; chIndex += 2; break; } int j; if (i >= BINOCULAROPERATORNUM) { for (j = 0;j < UNARYOPERATORNUM;j++) if (sourceCode[chIndex] == unaryOperators[j]) { tokenTable[tableIndex].line = line; tokenTable[tableIndex].type = UOPERATOR; tokenTable[tableIndex].token[0] = sourceCode[chIndex]; tokenTable[tableIndex].token[1] = 0; tableIndex++; chIndex++; break; } } int k; if (i == BINOCULAROPERATORNUM && j == UNARYOPERATORNUM) { for (k = 0;k < DELIMETERNUM;k++) { if (str[0] == delimeters[k]) { tokenTable[tableIndex].line = line; tokenTable[tableIndex].type = DELIMETER; tokenTable[tableIndex].token[0] = sourceCode[chIndex]; tokenTable[tableIndex].token[1] = 0; tableIndex++; chIndex++; break; } } } if (i == BINOCULAROPERATORNUM && j == UNARYOPERATORNUM && k == DELIMETERNUM) Error(UNKNOWNIDENTIFIER,line,str); } } tableNum = tableIndex; } void Emit(char* result,char* leftParameter,char* op,char* rightParameter) { cout << result << "=" << leftParameter << op << rightParameter << endl; } char* NewVar() { static int k = 0; k++; char* tempVar = new char[5]; tempVar[0] = 't'; char numtoch[5]; itoa(k,numtoch,10); strcmp(tempVar+1,numtoch); return tempVar; } char* Factor(int& tableIndex) { char* result = new char[MAXOFIDENTIFIER]; if (tokenTable[tableIndex].type == IDENTIFIER || tokenTable[tableIndex].type == INTEGER || tokenTable[tableIndex].type == FLOAT) { strcpy(result,tokenTable[tableIndex].token); tableIndex++; } else if (strcmp("(",to