我有结构,我为它分配内存:错误的分配大小或错误的自由方法的使用?
TRANSITION *transitions = malloc(sizeof(TRANSITION *));
我在程序的其他部分添加转场效果,所以我的realloc内存:
TRANSITION *transitions = source->transitions;
transitions = realloc(transitions, (numberTransitions + 1) * sizeof(TRANSITION *));
而且我有希望的方法释放内存:
free(transitions);
当我拨打免费方式获得:
"Aborted (core dumped)"
有什么不对?
整个代码:
#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
typedef struct STATE STATE;
typedef struct TRANSITION TRANSITION;
struct STATE
{
char name[4];
bool initial_state;
bool final_state;
TRANSITION *transitions;
int numberTransitions;
};
struct TRANSITION
{
char c;
STATE *destination;
};
STATE *create_state(char *name, bool is_initial, bool is_final);
void add_transition(STATE *source, char sign, STATE *dest);
void destroy_state(STATE **pp_state);
int main(void)
{
STATE *state0 = create_state("S'0", true, false);
STATE *state1 = create_state("S'1", false, false);
STATE *state2 = create_state("S'2", false, true);
STATE *zero_state = create_state("0", false, false);
add_transition(state0, 'a', state1);
add_transition(state0, 'b', zero_state);
add_transition(zero_state, 'a', zero_state);
add_transition(zero_state, 'b', zero_state);
add_transition(state1, 'a', state1);
add_transition(state1, 'b', state2);
add_transition(state2, 'a', state1);
add_transition(state2, 'b', state2);
destroy_state(&state0);
}
STATE *create_state(char *name, bool is_initial, bool is_final)
{
STATE *state = malloc(sizeof(STATE *));
strcpy(state->name, name);
state->initial_state = is_initial;
state->final_state = is_final;
state->transitions = NULL;
state->numberTransitions = 0;
return state;
}
void add_transition(STATE *source, char sign, STATE *dest)
{
if (source->transitions == NULL)
{
TRANSITION *transitions = malloc(sizeof(TRANSITION *));
transitions->c = sign;
transitions->destination = malloc(sizeof(STATE *));
transitions->destination = dest;
source->transitions = transitions;
source->numberTransitions = 1;
}
else
{
TRANSITION *transitions = source->transitions;
int numberTransitions = source->numberTransitions;
transitions = realloc(transitions, (numberTransitions + 1) * sizeof(TRANSITION *));
transitions[numberTransitions].c = sign;
transitions[numberTransitions].destination = dest;
(source->numberTransitions)++;
}
}
void destroy_state(STATE **pp_state)
{
TRANSITION *transitions = (*pp_state)->transitions;
// free(transitions->destination);
// transitions->destination = NULL;
free(transitions);
// transitions = NULL;
// free(pp_state);
// pp_state = NULL;
}
我确定你想分配'sizeof(TRANSITION)',因为现在你只需要为指针分配足够的空间,而不是实际上指向的是什么。我希望你能保存'realloc'的价值,不要试图释放原来的东西。很难说,因为你没有显示实际的代码。 –
@AlexD我以前有过,但一切都搞砸了。我的字符看起来像这样。显然有些内存错误 – Goldi
当你使用'realloc'时,你的指针可能指向一个新的地方,你也可能会收到一个返回值'NULL' - 你确定你释放了正确的指针(不是旧地址)吗?此外,您在代码中没有执行**任何**错误处理,您忽略了可能的意外情况,并且显然忽略了编译器警告......使用编译器警告,它们可以帮助您! – Myst