c - strcmp 改变字符串的值

Question

void search(char*** p, int numOfWords, int* pNumOfDefArr){
int i, j, index;
char* word = (char*)malloc(WORD_SIZE * sizeof(char));
for (i = 0; i < N; i++) //just clearing the screen
    printf("\n");
printf("Hello and thank you for filling Dictionary 1.0 with new words!!\n");
printf("Which word are you looking for??\n");
gets(word);
fix_word(word, 0);
while (strcmp(word, "Exit")){
    index = (search_word(p, word, 0, numOfWords - 1, 0));
    if (index < 0)
        printf("Unknown word!!!!!!\n");
    else{
        for (j = 0; j < pNumOfDefArr[index]; j++)
            printf("%s\n", *(*(p + index) + 1 + j));
    }
    free(word);
    char* word = (char*)malloc(WORD_SIZE * sizeof(char));
    printf("Looking for another word?\n");
    gets(word);
    fix_word(word, 0);
}
printf("Farewell!!\n");

在调试器上，我可以看到第 10 行:while (strcmp(word, "Exit")) word 的值为 从 "asd" 更改为 "Error reading characters of string." 为什么会这样？

这是 fix_word() 函数的代码:

void fix_word(char* pword, int j){
    if (*(pword + j) != '\0'){
        if (j == 0 && (*(pword + j) >= 'a' && *(pword + j) <= 'z')){
            *pword -= N;
            j++;
        }
        else if (*(pword + j) >= 'A' && *(pword + j) <= 'Z'){
            *(pword + j) += N;
            j++;
        }
        else
            j++;
        fix_word(pword, j);
    }
}

Answer 1

这称为作用域。

char* word = (char*)malloc(WORD_SIZE * sizeof(char));     /* 1 */
while (strcmp(word, "Exit")){                             /* 1 */
    free(word);                                           /* 1 and gone */
    char* word = (char*)malloc(WORD_SIZE * sizeof(char)); /* 2 */
}

您已经在两个不同的范围内声明了变量“word”，并且混合使用了它。

如果省略第二个“char *”，一切都会好起来的。