load() 函数的问题(CS50 问题集 5:拼写)
Problem with load() function (CS50 Problem Set 5: Speller)
我正在研究 CS50 的问题集 5(拼写),但我不明白 load() 函数哪里出了问题。当我尝试编译时,第 36 行和第 79 行出现错误。但我不明白如何解决它。我是 CS 的新手,所以如果这很明显,我很抱歉。
我认为我的问题与 strcpy 和 strcmp 函数有关,但据我所知,我正在按照 CS50 手册页中的说明使用这些函数。但是,很明显我遗漏了一些东西,否则它会起作用。
提前致谢!!
// Implements a dictionary's functionality
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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
unsigned long word_count;
const unsigned int N = 26;
// Hash table
node *table[N];
// Returns true if word is in dictionary, else false
bool check(const char *word)
{
// Find hash location for current word
int h = hash(word);
// Create cursor to keep track of location on linked list at hash location
node *cursor = table[h] -> next;
while (cursor != NULL)
{
// If word is found
if (strcmp(cursor -> word, word) == 0)
{
return true;
}
// If word is not at current cursor location
else
{
cursor = cursor -> next;
}
}
// If word is not found in linked list at hash location
return false;
}
// Hashes word to a number
unsigned int hash(const char *word)
{
// TODO: Improve this hash function
return toupper(word[0]) - 'A';
}
// Loads dictionary into memory, returning true if successful, else false
bool load(const char *dictionary)
{
// Initialise number of words loaded from dictionary
word_count = 0;
// Open dictionary file from command line
FILE *dict = fopen(dictionary, "r");
if (dict == NULL)
{
return false;
}
// Read words from dictionary one by one
char buffer[LENGTH + 1];
while (fscanf(dict, "%s", buffer) != EOF)
{
// Create new node for current word
node *n = malloc(sizeof(node));
if (n == NULL)
{
return false;
}
// Copy current word to created node
strcpy(n -> word, buffer);
// Assign node to the hash table
int h = hash(buffer);
// Node does not already exist at hash location
if (table[h] -> next == NULL)
{
n -> next = NULL;
table[h] -> next = n;
}
// Node already exists at hash location
else
{
n -> next = table[h] -> next;
table[h] -> next = n;
}
// Update counter for words loaded from dictionary
word_count++;
}
fclose(dict);
// Dictionary successfully loaded
return true;
}
// Returns number of words in dictionary if loaded, else 0 if not yet loaded
unsigned int size(void)
{
return word_count;
}
// Unloads dictionary from memory, returning true if successful, else false
bool unload(void)
{
// TODO
return false;
}
节点定义与发行版代码不一样; word
应该是一个字符数组而不是一个字符指针数组。 node->word
是字符串函数中使用的错误类型。
我正在研究 CS50 的问题集 5(拼写),但我不明白 load() 函数哪里出了问题。当我尝试编译时,第 36 行和第 79 行出现错误。但我不明白如何解决它。我是 CS 的新手,所以如果这很明显,我很抱歉。 我认为我的问题与 strcpy 和 strcmp 函数有关,但据我所知,我正在按照 CS50 手册页中的说明使用这些函数。但是,很明显我遗漏了一些东西,否则它会起作用。 提前致谢!!
// Implements a dictionary's functionality
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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
unsigned long word_count;
const unsigned int N = 26;
// Hash table
node *table[N];
// Returns true if word is in dictionary, else false
bool check(const char *word)
{
// Find hash location for current word
int h = hash(word);
// Create cursor to keep track of location on linked list at hash location
node *cursor = table[h] -> next;
while (cursor != NULL)
{
// If word is found
if (strcmp(cursor -> word, word) == 0)
{
return true;
}
// If word is not at current cursor location
else
{
cursor = cursor -> next;
}
}
// If word is not found in linked list at hash location
return false;
}
// Hashes word to a number
unsigned int hash(const char *word)
{
// TODO: Improve this hash function
return toupper(word[0]) - 'A';
}
// Loads dictionary into memory, returning true if successful, else false
bool load(const char *dictionary)
{
// Initialise number of words loaded from dictionary
word_count = 0;
// Open dictionary file from command line
FILE *dict = fopen(dictionary, "r");
if (dict == NULL)
{
return false;
}
// Read words from dictionary one by one
char buffer[LENGTH + 1];
while (fscanf(dict, "%s", buffer) != EOF)
{
// Create new node for current word
node *n = malloc(sizeof(node));
if (n == NULL)
{
return false;
}
// Copy current word to created node
strcpy(n -> word, buffer);
// Assign node to the hash table
int h = hash(buffer);
// Node does not already exist at hash location
if (table[h] -> next == NULL)
{
n -> next = NULL;
table[h] -> next = n;
}
// Node already exists at hash location
else
{
n -> next = table[h] -> next;
table[h] -> next = n;
}
// Update counter for words loaded from dictionary
word_count++;
}
fclose(dict);
// Dictionary successfully loaded
return true;
}
// Returns number of words in dictionary if loaded, else 0 if not yet loaded
unsigned int size(void)
{
return word_count;
}
// Unloads dictionary from memory, returning true if successful, else false
bool unload(void)
{
// TODO
return false;
}
节点定义与发行版代码不一样; word
应该是一个字符数组而不是一个字符指针数组。 node->word
是字符串函数中使用的错误类型。