C++ 为什么我在我的代码中得到错误和退出代码1073741819(0xC0000005)，但如果我添加了一个不相关的打印语句，它仍然有效

我对C语言还很陌生，所以我不知道这里会发生什么.

在应该以面向对象的方式运行的String struct 的这个实现中，当我得到以下诊断时，set函数中似乎有一些错误:

Process finished with exit code -1073741819 (0xC0000005)

这是我的.h文件:

#include <string.h>
#include <stdbool.h>

typedef struct String_Struct
{
    char* value;
    unsigned int length;

    void (*set) (struct String_Struct* self, char* value);
    bool (*equals) (const struct String_Struct* self, const struct String_Struct* other);
    int (*compareTo) (const struct String_Struct* self, const struct String_Struct* other);
    void (*concat) (struct String_Struct* self, const struct String_Struct* other);
    void (*freeString) (struct String_Struct* self);
} String;

String* newString (char* value);
void set (String* self, char* value);
bool equals (const String* self, const String* other);
int compareTo (const String* self, const String* other);
void concat (String* self, const String* other);
void freeString (String* self);

以下是它的实现:

#include "mystring.h"
#include <stdlib.h>
#include <stdio.h>

void set (String* self, char* value)
{
    // Only proceed if self and value exist
    if (!self || !value)
    {
        return;
    }

    free(self->value);
    self->length = strlen(value) + 1;
    self->value = (char*) malloc(sizeof(char) * self->length);
    strcpy(self->value, value);
}

int compareTo (const String* self, const String* other)
{
    if ((!self && other) || (self && !other))
        return INT_MIN;

    return strcmp(self->value, other->value);
}

bool equals (const String* self, const String* other)
{
    if ((!self && other) || (self && !other))
        return false;

    if (self == other)
        return true;

    return strcmp(self->value, other->value) == 0;
}

void concat (String* self, const String* other)
{
    if (!self || !other)
    {
        return;
    }

    char* result = (char*) malloc(sizeof(char) * (strlen(self->value) + strlen(other->value) + 2));

    strcpy(result, self->value);
    strcat(result, other->value);

    self->set(self, result);
}

void freeString (String* self)
{
    free(self->value);
    free(self);
}

String* newString (char* value)
{
    String* str = (String*) malloc(sizeof(String));

    str->set = &set;
    str->equals = &equals;
    str->compareTo = &compareTo;
    str->concat = &concat;
    str->freeString = &freeString;

    str->set(str, value);

    return str;
}

这是我的主电源.

#include <stdio.h>
#include "mystring.h"

int main()
{
    String* string = newString("Hello");

    printf("%s", string->value);

    return 0;
}

当我运行这段代码时，我得到了上面提供的错误.但当我在"set"中添加一个不相关的printf语句时，如下所示:

void set (String* self, char* value)
{
    // Only proceed if self and value exist
    if (!self || !value)
    {
        return;
    }

    printf("Debug");

    free(self->value);
    self->length = strlen(value) + 1;
    self->value = (char*) malloc(sizeof(char) * self->length);
    strcpy(self->value, value);
}

以下是控制台输出: 调试Hello 进程已完成，退出代码为-1073741819(0xC0000005)

有谁能解释一下原因吗？