c - free() 不接受结构类型

Question

#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);

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;
        size_t new_size = sizeof(transitions) + sizeof(TRANSITION);
        transitions = realloc(transitions, new_size);
        transitions[numberTransitions].c = sign;
        transitions[numberTransitions].destination = dest;
        (source->numberTransitions)++; 
    }
}

void destroy_state(STATE **pp_state) {
    TRANSITION *transitions = (*pp_state)->transitions;
    int numberTransitions = (*pp_state)->numberTransitions;
    int i = 0;
    for (i = 0; i < numberTransitions; i++) {
        free(transitions[i]);
        transitions[i] = NULL;
    }
}

我的异常(exception)是 transitions[i] 的类型与 methods 参数不兼容。该方法调用有什么问题？ Transitions 是一种结构。

编辑:我添加了其他方法，因为它是被请求的。

EDIT2: 好的，我发现如果我的 STATE 只有一个 TRANSITION，我可以释放 TRANSITION 指针。所以我的猜测是，当我尝试为额外的转换重新分配内存时，我在重新分配时犯了一个错误。

size_t new_size = sizeof(transitions) + sizeof(TRANSITION);
transitions = realloc(transitions, new_size);

Answer 1

free(transitions[i]);

transitions[i] 不是要传递给 free 的任何指针类型。 transitions 是指向结构的指针，但 transition[i] 变成了结构变量(不是指针类型)，因此不应传递给 免费 .

这样做-

free(transitions);