GLib哈希表循环问题 [英] GLib Hash Table Loop Problem

问题描述

我将在C程序中使用 GLib 的哈希表实现，目前 我只是在尝试.我编写了以下代码进行测试:

I am going to use GLib's Hash table implementation in a C program and just for now I am just experimenting with it. I wrote the following piece of code for testing:

 #include <glib.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>

 int main(){
 // Some codes and declerations here
 GHashTable *g_hash_table;
 uint32_t *a;
 a=(uint32_t *)malloc(sizeof(uint32_t));
 if(a==NULL){
    printf("Not Enough Mem For a\n");
    return 1;
 }
 *a=1123231;

 uint32_t* key;
 key=(uint32_t *)malloc(sizeof(uint32_t));
 if(key==NULL){
     printf("Not Enough Mem For key\n");
     return 1;
 }
 *key=122312312;
 int i;
 g_hash_table=g_hash_table_new(g_int_hash, g_int_equal);
 for(i=0;i<TABLE_SIZE;i++){
     *key+=1;
     *a+=1;
     g_hash_table_insert(g_hash_table,(gpointer)key,(gpointer)a);
     uint32_t *x=(uint32_t *)g_hash_table_lookup(g_hash_table,key);
     printf("Counter:%d,  %u\n",i,*x);
 }

GHashTableIter iter;
g_hash_table_iter_init(&iter,g_hash_table);
int size=g_hash_table_size(g_hash_table);
printf("First size: %d\n",size);
uint32_t *val;
uint32_t *key_;
int counter=0;

// My problem is in the following loop it 
// always returns the same and the last key value pair
 while(g_hash_table_iter_next(&iter,(gpointer*)(void*)&key_,(gpointer*)(void*)&val)){
     counter++;
     printf("%u %u\n",(uint32_t)*key_,(uint32_t)*val);
     printf("Counter: %d\n",counter);
 }
 //Some more code here        
    return 0;
}

以某种方式，我的测试代码可以正确迭代，但是在循环中，它始终返回最后一个键和最后一个值对，并且始终相同.这里有什么问题?上面的代码可能无法按其格式运行.我只是复制并粘贴了一些部分，以使我对自己想做的事情有个清晰的认识.

Somehow my test code iterates correctly but in the loop it always returns the last key and last value pairs and it is always the same. What is the problem here? The above code may not run with its as it is format. I just copied and pasted some parts to give a clear idea about what I am trying to do.

推荐答案

key，a声明中有错误.您总是将相同的指针放在哈希表中.试试:

There is an error in key, a declarations. You always put the same pointer in the hash table. Try:

#include <glib.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#define TABLE_SIZE 12

int main() {
    // Some codes and declarations here
    GHashTable *g_hash_table;
    int i;

    g_hash_table = g_hash_table_new(g_int_hash, g_int_equal);
    for (i=0; i<TABLE_SIZE; i++)
    {
        uint32_t* key = (uint32_t *)malloc(sizeof(uint32_t));
        uint32_t* a = (uint32_t *)malloc(sizeof(uint32_t));
        *key = i;
        *a   = i+10;
        g_hash_table_insert(g_hash_table, (gpointer)key, (gpointer)a);
        uint32_t *x = (uint32_t *)g_hash_table_lookup(g_hash_table,key);
        printf("key: %d -->  %u\n", *key ,*x);
    }

    GHashTableIter iter;
    int size=g_hash_table_size(g_hash_table);
    printf("First size: %d\n", size);

    uint32_t *val;
    uint32_t *key_;

    // My problem is in the following loop
    // it always returns the same and the last key value pair

    g_hash_table_iter_init (&iter, g_hash_table);
    while (g_hash_table_iter_next (&iter, (gpointer) &key_, (gpointer) &val))
    {
        printf("key %u ---> %u\n", (uint32_t)*key_, (uint32_t)*val);
    }

    // TODO: free keys
    return 0;
}

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