cd5 left factoring

//A->ab|cd|ef no
//A->ab|ac|d
//A->aA'
//A'->b|c

#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define MAX 100

void longestCommonPrefix(char *result, char *str1, char *str2) {
    int i = 0;
    while (str1[i] && str2[i] && str1[i] == str2[i]) {
        result[i] = str1[i];
        i++;
    }
    result[i] = '\0';
}

void checkLeftFactoring(char nonTerminal, char *productions) {
    char commonPrefix[MAX] = "", remainingParts[MAX][MAX];
    int hasLeftFactoring = 0, partCount = 0;

    for (char *token = strtok(productions, "|"), *prev = NULL; token; token = strtok(NULL, "|")) {
        if (prev) {
            char tempPrefix[MAX];
            longestCommonPrefix(tempPrefix, prev, token);
            if (*tempPrefix) {
                hasLeftFactoring = 1;
                strcpy(commonPrefix, tempPrefix);
                strcpy(remainingParts[partCount++], prev + strlen(tempPrefix));
                strcpy(remainingParts[partCount++], token + strlen(tempPrefix));
            }
        }
        prev = token;
    }

    if (hasLeftFactoring) {
        printf("Left Factoring Grammar Detected.\n");
        printf("%c -> %s%c'\n", nonTerminal, commonPrefix, nonTerminal);
        printf("%c' -> ", nonTerminal);
        for (int i = 0; i < partCount; i++) {
            printf("%s%s", *remainingParts[i] ? remainingParts[i] : "e", (i < partCount - 1) ? " | " : "\n");
        }
    } else {
        printf("No Left Factoring detected.\n");
    }
}

int main() {
    char input[MAX];

    printf("Enter the production rule (e.g., A->ab|ac|d): ");
    fgets(input, MAX, stdin);
    input[strcspn(input, "\n")] = '\0';

    if (!isupper(input[0]) || strncmp(input + 1, "->", 2) != 0) {
        printf("Error: Invalid production rule format.\n");
        return 0;
    }

    checkLeftFactoring(input[0], input + 3);
    return 0;
}