CS50 pset5 拼写器 [2022] - " :( program is free of memory errors"



我得到错误";(程序是免费的内存错误valgrind测试失败;查看日志获取更多信息。">

下面是我的代码:
// Implements a dictionary's functionality
#include <ctype.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <stdio.h>
#include "dictionary.h"
// Represents a node in a hash table
typedef struct node
{
char word[LENGTH + 1];
struct node *next;
}
node;
// TODO: Choose number of buckets in hash table
const unsigned int N = 26;
// Hash table
node *table[N];
//Declare variables
unsigned int word_count;
unsigned int hash_value;
// Returns true if word is in dictionary, else false
bool check(const char *word)
{
// TODO
hash_value = hash(word);
node *cursor = table[hash_value];

// Go in link list
while (cursor != 0)
{
if (strcasecmp(word, cursor->word) == 0)
{
return true;
}
cursor = cursor->next;
}
return false;
}
// Hashes word to a number
unsigned int hash(const char *word)
{
// TODO: Improve this hash function
unsigned long total = 0;
for (int i = 0; i < strlen(word); i++)
{
total += tolower(word[i]);
}
return total % N;
}
// Loads dictionary into memory, returning true if successful, else false
bool load(const char *dictionary)
{
// Open dictionary
FILE *file = fopen(dictionary, "r");
// it would be null if cant be open
if (file == NULL)
{
printf("Unable to open %sn", dictionary);
return false;
}
// Declare variable words
char word[LENGTH + 1];
//Scan dictionary for strings up until EOF
while (fscanf(file, "%s", word) != EOF)
{
node *n = malloc(sizeof(node));
if (n == NULL)
{
return false;
}
//copy wordds into node
strcpy(n->word, word);
hash_value = hash(word);
n->next = table[hash_value];
table[hash_value] = n;
word_count++;
}
fclose(file);
return true;
}
// Returns number of words in dictionary if loaded, else 0 if not yet loaded
unsigned int size(void)
{
if (word_count > 0)
{
return word_count;
}
return 0;
}
// Unloads dictionary from memory, returning true if successful, else false
bool unload(void)
{
for (int i = 0; i < N; i++)
{
node *cursor = table[i];
while (cursor)
{
node *tmp = cursor;
cursor = cursor->next;
free(tmp);
}
if (cursor == NULL)
{
return true;
}
}
return false;
}

下面是valgrind check50的错误:程序没有内存错误,测试失败;有关更多信息,请参阅log。这是ERR日志:(file: dictionary.c, line: 80)

第80行代码是:

while (fscanf(file, "%s", word) != EOF)
{
node *n = malloc(sizeof(node));
if (n == NULL)
{
return false;
}

unload将释放一个索引并返回到拼写器,因为这个if (cursor == NULL)块。索引中的最后一个节点应该将游标设置为NULL,这样函数就完成了。这个条件应该取消。在unload中确实没有返回false的条件。

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