Pset5(Speller)无内存泄漏却触发Valgrind未初始化值错误求助

Let's break down the root cause of your Valgrind warning first:

The error points to this line in your check function:

lower[i] = tolower(word[i]);

Your current loop runs fixed LENGTH + 1 times, but the input word is a null-terminated C string—most words will be shorter than LENGTH (which is 45 for Pset5). When i exceeds the actual length of word (after hitting the \0 terminator), you're still reading from word[i], and those memory positions are uninitialized. Valgrind flags this because it detects you're using uninitialized data in subsequent operations (like passing lower to your hash function).

How to Fix It #

Instead of looping through all LENGTH + 1 positions, only iterate until you hit the null terminator of word, then explicitly terminate the lower array to keep it a valid C string:

bool check(const char *word) {
    char lower[LENGTH + 1];
    int i = 0;
    // Convert only the actual characters in word to lowercase
    while (word[i] != '\0') {
        lower[i] = tolower(word[i]);
        i++;
    }
    // Ensure the lowercase string is properly null-terminated
    lower[i] = '\0';

    node *tmp = table[hash(lower)];
    while (tmp != NULL) {
        // Since tmp->word is lowercase, we can use strcmp instead of strcasecmp for efficiency
        if (strcmp(lower, tmp->word) == 0) {
            return true;
        }
        tmp = tmp->next;
    }
    return false;
}

A bonus optimization: since your dictionary stores all lowercase words, using strcmp(lower, tmp->word) instead of strcasecmp(word, tmp->word) avoids redundant case checking and is faster.

Quick Side Note #

Your size function has a logical error that might cause unexpected behavior later:

if (&load == false) {
    return '0';
}

Comparing the function pointer &load to false doesn't make sense. Instead, use your global count variable to check if the dictionary was loaded—if count == 0, return 0 (as an integer, not the character '0'):

unsigned int size(void) {
    return count;
}

Because count starts at 0 and only increments during a successful load, this correctly returns 0 when no words are loaded, and the actual count otherwise.

内容的提问来源于stack exchange，提问作者Bunnycorn