设计一个可以读入text文件并计算文法中所有变量的FIRSTOP 集的c语言程序

好的，以下是一个可以读入text文件并计算文法中所有变量的FIRSTOP集的c语言程序：

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

#define MAX_RULES 100
#define MAX_NONTERMINALS 10
#define MAX_TERMINALS 20

char rules[MAX_RULES][MAX_NONTERMINALS + 3];
char nonterminals[MAX_NONTERMINALS], terminals[MAX_TERMINALS];
int num_rules = 0, num_nonterminals = 0, num_terminals = 0;

int is_nonterminal(char c) {
    for (int i = 0; i < num_nonterminals; i++) {
        if (nonterminals[i] == c) {
            return 1;
        }
    }
    return 0;
}

int is_terminal(char c) {
    for (int i = 0; i < num_terminals; i++) {
        if (terminals[i] == c) {
            return 1;
        }
    }
    return 0;
}

void add_nonterminal(char c) {
    if (!is_nonterminal(c)) {
        nonterminals[num_nonterminals++] = c;
    }
}

void add_terminal(char c) {
    if (!is_terminal(c)) {
        terminals[num_terminals++] = c;
    }
}

void add_firstop(char c, char op) {
    for (int i = 0; i < num_rules; i++) {
        if (rules[i][0] == c) {
            if (!is_terminal(op)) {
                add_nonterminal(op);
            }
            for (int j = 1; j < strlen(rules[i]); j++) {
                if (rules[i][j] == c) {
                    if (j == strlen(rules[i]) - 1) {
                        add_firstop(rules[i][0], op);
                    } else {
                        if (is_terminal(rules[i][j + 1])) {
                            add_terminal(rules[i][j + 1]);
                        } else {
                            add_firstop(rules[i][j + 1], op);
                        }
                    }
                }
            }
        }
    }
}

void calculate_firstop() {
    for (int i = 0; i < num_nonterminals; i++) {
        add_firstop(nonterminals[i], nonterminals[i]);
    }
}

void print_firstop() {
    for (int i = 0; i < num_nonterminals; i++) {
        printf("FIRSTOP(%c) = { ", nonterminals[i]);
        for (int j = 0; j < num_terminals; j++) {
            for (int k = 0; k < num_rules; k++) {
                if (rules[k][0] == nonterminals[i]) {
                    for (int l = 1; l < strlen(rules[k]); l++) {
                        if (rules[k][l] == terminals[j]) {
                            printf("%c, ", terminals[j]);
                            break;
                        } else if (rules[k][l] == nonterminals[i]) {
                            break;
                        }
                    }
                }
            }
        }
        printf("}\n");
    }
}

int main() {
    FILE *fp;
    char filename[100], c;

    printf("Enter the name of the file to read from: ");
    scanf("%s", filename);

    fp = fopen(filename, "r");

    while ((c = fgetc(fp)) != EOF) {
        if (c == '\n') {
            num_rules++;
        }
    }

    rewind(fp);

    for (int i = 0; i < num_rules; i++) {
        fgets(rules[i], MAX_NONTERMINALS + 3, fp);
        add_nonterminal(rules[i][0]);
        for (int j = 1; j < strlen(rules[i]); j++) {
            if (isupper(rules[i][j])) {
                add_nonterminal(rules[i][j]);
            } else if (islower(rules[i][j])) {
                add_terminal(rules[i][j]);
            }
        }
    }

    calculate_firstop();

    print_firstop();

    fclose(fp);

    return 0;
}

该程序首先会读入一个文本文件，然后计算文法中所有变量的FIRSTOP集并将其打印出来。程序会先读入文法的产生式，然后计算每个非终结符的FIRSTOP集。在计算FIRSTOP集时，程序会遍历每个产生式，对于每个非终结符，它会找到产生式中所有该非终结符的出现位置，然后根据该非终结符后面的符号来计算FIRSTOP集。如果该符号是终结符，则将其加入终结符集合中；否则，将递归计算该符号的FIRSTOP集。最后，程序将所有非终结符的FIRSTOP集打印出来。

注意，该程序假设文法中的符号都是单个字符。如果有多个字符的符号，需要修改程序以支持这种情况。此外，该程序并没有对文法进行语法检查，因此需要确保输入的文法是正确的。