所以我为一个名为Objective的结构实现了一个单独链接的哈希表，这样我就可以对所述目标执行一些操作。目前我有这个：
Hashtable.h：
#ifndef HASHTABLE_H
#define HASHTABLE_H
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
/*Using separate chaining to store the obejctives*/
typedef struct Objective{
char name [8000];
unsigned long id, duration, deps [9000];
int hasDeps;
}*pObjective;
typedef struct nodehash{ /*Node of list*/
pObjective obj;
struct nodehash*next;
}*link;
void Init(int M);
int search(unsigned long id);
void insert(pObjective o);
void delete(unsigned long id);
link insertBegin(link h, pObjective obj);
int searchList(link h, unsigned long id);
link removeList(link h, unsigned long id);
pObjective searchObj(unsigned long id);
pObjective searchObjAux(link h, unsigned long id);
#endif
Objectives.c：
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "OBJECTIVES.h"
/*Checks if all inserted dependencies already exist*/
int existDeps(unsigned long dep[9000]){
int i, count = 0;
for(i = 0; i < 9000; i++){
if(search(dep[i]) != 0)
count++;
}
return count;
}
/ *Adds objective with dependencies*/
void addObj(unsigned long id, char name [8000], unsigned long duration,
unsigned long dep[9000]){
int i;
pObjective obj = malloc(sizeof(pObjective));
obj->id = id;
obj->duration = duration;
obj->hasDeps = 1;
strcpy(name, obj->name);
for(i = 0; i < 9000; i++){
obj->deps[i] = dep[i];
}
if(search(id) != 0)
printf("id already exists\n");
else if(existDeps(dep) != 0)
printf("no such task\n");
else
insert(obj);
free(obj);
}
/*Adds objective with no dependencies*/
void addNoDeps(unsigned long id, char name [8000], unsigned long
duration){
pObjective obj = malloc(sizeof(pObjective));
obj->id = id;
obj->duration = duration;
obj->hasDeps = 1;
strcpy(name, obj->name);
if(search(id) != 0)
printf("id already exists\n");
else
insert(obj);
free(obj);
}
/*Removes objective with no dependencies*/
void removeObj(unsigned long id){
int res = search(id);
pObjective obj = searchObj(id);
if(res == 0)
printf("no such task\n");
else if(obj->hasDeps == 1)
printf("task with dependencies\n");
else
delete(id);
}
Objectives.h：
#ifndef OBJECTIVES_H
#define OBJECTIVES_H
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "HASHTABLE.h"
/*Functions to work with objectives*/
int existDeps(unsigned long dep[9000]);
void addObj(unsigned long id, char name [8000], unsigned long duration,
unsigned long dep[9000]);
void addNoDeps(unsigned long id, char name [8000], unsigned long
duration);
void removeObj(unsigned long id);
#endif
Hashtable.c：
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "HASHTABLE.h"
#define hash(A,B) (A%B) /*Hash function*/
static link *heads;
static int M;
/*Initiates hashtable with size m*/
void Init(int m){
int i;
M = m;
heads = (link*)malloc(M*sizeof(link));
for(i = 0; i < M; i++)
heads[i] = NULL;
}
/*Searches objective with said id*/
int search(unsigned long id){
int i = hash(id, M);
return searchList(heads[i], id);
}
/*Inserts objective into hashtable*/
void insert(pObjective o){
int i = hash(o->id, M);
heads[i] = insertBegin(heads[i], o);
}
/*Deletes objective using it's id*/
void delete(unsigned long id){
int i = hash(id, M);
heads[i] = removeList(heads[i], id);
}
/*Returns objective with said id*/
pObjective searchObj(unsigned long id){
int i = hash(id, M);
return searchObjAux(heads[i], id);
}
/*Inserts objective into list*/
link insertBegin(link h, pObjective obj){
link new = (link)malloc(sizeof(struct nodehash));
new->obj = obj;
new->next = h;
return new;
}
/*Searches objective by id in a list*/
int searchList(link h, unsigned long id){
link t;
int count = 0;
for(t = h; t != NULL; t = t->next){
if(t->obj->id == id)
count++;
}
return count++;
}
/*Removes objective from list*/
link removeList(link h, unsigned long id){
link t, x, z;
for(t = h; t != NULL; t = t->next){
if(t->next->obj->id == id)
x = t;
}
z = x->next;
x->next = z->next;
free(z);
return h;
}
/*Returns objetive from said id from list*/
pObjective searchObjAux(link h, unsigned long id){
link t, x;
for(t = h; t != NULL; t = t->next){
if(t->obj->id == id)
x = t;
}
return x->obj;
}
我正在快速测试功能addObj（添加一个带有依赖项的目标）和addNoDeps（在没有依赖项的情况下添加一个目标）：
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "OBJECTIVES.h"
int main(){
unsigned long array [1] = {3};
Init(11);
addNoDeps(1, "tarefa1", 20);
addObj(2, "tarefa2", 20, array);
return 0;
}
但我不断得到分段错误（核心转储），我无法弄清楚原因。我的实施错了吗？功能有误吗？我无法解决问题，有人可以帮助我吗？
答案 0 :(得分：1)
我现在无法运行您的代码，所以我无法分析核心转储，但我相信您正在尝试访问已经释放的内存。在addNoDeps结束时，将它放入列表后释放pObjective。然后，当你addObj之后，搜索列表并检查以确保与其关联的链接对象不为空。特别是这段代码：
for(t = h; t != NULL; t = t->next){
if(t->obj->id == id)
count++;
您只检查t（链接指针）是否为空，但由于您释放了前一个对象，因此t-＆gt; obj指针不指向初始化的memroy。因此，尝试通过t-＆gt; obj-＆gt; id访问它是访问未初始化的内存。如果你删除addNoDeps和addObj函数末尾的free(obj)，你应该没问题。您可能还想添加检查以确保t-＆gt; obj也不为空。一般来说，分段错误是由访问未初始化的内存引起的，所以在调试时检查访问指针后的free，double frees等等。在这些情况下，学习使用GDB也可以提供很多帮助。