写一个c语言消除文法左递归代码

以下是一个简单的消除文法左递归的C语言代码： ```c #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_RULES 100 // 最大产生式数量 #define MAX_LENGTH 100 // 最大产生式长度 char rules[MAX_RULES][MAX_LENGTH]; // 存储产生式 int numRules = 0; // 产生式数量 // 检查是否有左递归，并进行消除 void eliminateLeftRecursion(char nonTerminal) { int i, j; int hasLeftRecursion = 0; // 检查是否有左递归 for (i = 0; i < numRules; i++) { if (rules[i][0] == nonTerminal && rules[i][2] == nonTerminal) { hasLeftRecursion = 1; break; } } // 如果有左递归，则进行消除 if (hasLeftRecursion) { char newNonTerminal = nonTerminal + 1; int numNewRules = 0; char newRules[MAX_RULES][MAX_LENGTH]; // 生成新的非终结符和产生式 for (i = 0; i < numRules; i++) { if (rules[i][0] == nonTerminal) { // 消除左递归 int length = strlen(rules[i]); for (j = 2; j < length; j++) { newRules[numNewRules][j - 2] = rules[i][j]; } newRules[numNewRules][length - 2] = newNonTerminal; newRules[numNewRules][length - 1] = '\0'; numNewRules++; } } newRules[numNewRules][0] = '\0'; strcpy(rules[numRules], newNonTerminal); strcat(rules[numRules], "->"); strcat(rules[numRules], "epsilon"); numRules++; // 添加新的产生式 for (i = 0; i < numRules; i++) { if (rules[i][0] == nonTerminal) { // 添加新的产生式 int length = strlen(rules[i]); rules[i][length - 1] = newNonTerminal; rules[i][length] = '\0'; } } // 添加原来的产生式 for (i = 0; i < numNewRules; i++) { strcat(rules[numRules], newRules[i]); strcat(rules[numRules], newNonTerminal); numRules++; } // 递归消除新的非终结符的左递归 eliminateLeftRecursion(newNonTerminal); } } int main() { int i; // 输入产生式 printf("请输入产生式（以#结束）：\n"); while (1) { char rule[MAX_LENGTH]; scanf("%s", rule); if (rule[0] == '#') { break; } strcpy(rules[numRules], rule); numRules++; } // 消除左递归 for (i = 0; i < numRules; i++) { eliminateLeftRecursion(rules[i][0]); } // 输出消除左递归后的产生式 printf("消除左递归后的产生式：\n"); for (i = 0; i < numRules; i++) { printf("%s\n", rules[i]); } return 0; } ```