抛出异常：读取访问冲突。 **head** 是 0xCCCCCCCC。发生了

Question

我正在用 C 编写一个链接列表。这是我的代码。我在这里看不到任何逻辑错误，但是在while循环中打印时，在打印最后一个节点后它不会跳出循环而是继续循环然后给我这个错误“抛出异常：读取访问冲突。head 是 0xCCCCCCCC。发生在循环中的“头”指针上。

// ass0.c
#define _CRT_SECURE_NO_WARNINGS
#define _CRTDBG_MAP_ALLOC // need this to get the line identification
//_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF|_CRTDBG_LEAK_CHECK_DF); // in main, after local declarations
//NB must be in debug build
#include <crtdbg.h>
#include <stdio.h>
#include <string.h>
typedef enum { FALSE = 0, TRUE } BOOL;
struct Frame {
char* frameName;
struct Frame* pNext;
};
typedef struct {
char* animationName;
struct Frame* frames;
}Animation;
// Forward declarations
void InitAnimation(Animation*);
void InsertFrame(Animation*);
//void DeleteFrame(Animation*);
//void EditFrame(Animation*);
void ReportAnimation(Animation*);
//void CleanUp(Animation*);
int main(void)
{
char response;
BOOL RUNNING = TRUE;
Animation RG;
_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
InitAnimation(&RG);
while (RUNNING)
{
    printf("MENU\n 1. Insert a Frame at the front\n 2. Delete last Frame\n 3. Edit a Frame\n 4. Report the Animation\n 5. Quit\n");
    scanf("%c", &response);
    switch (response)
    {
    case '1':InsertFrame(&RG); break;
    //case '2':DeleteFrame(&RG); break;
    //case '3':EditFrame(&RG); break;
    case '4':ReportAnimation(&RG); break;
    //case '5':RUNNING = FALSE; CleanUp(&RG); break;
    default:printf("Please enter a valid option\n");
    }
}
return 0;
  }

  void InitAnimation(Animation* newAnimation) {
newAnimation = malloc(sizeof(Animation));
newAnimation->animationName = "Animation_1";
newAnimation->frames = NULL;
 }

 void InsertFrame(Animation* animation) {
printf("Insert a Frame in the Animation\n");
char fName[50];
printf("Please enter the Frame Name: ");
scanf("%s", fName);

struct Frame *newFrame; 
newFrame = malloc(sizeof(struct Frame));
int nameSize = strlen(fName);
newFrame->frameName = malloc(nameSize + 1);
strcpy(newFrame->frameName, fName);
newFrame->pNext = 0;

//struct Frame* head;

if (animation->frames == NULL) 
    animation->frames = newFrame;
    //head = animation->frames;
    //head->pNext = NULL;
    //head = animation->frames;


else {
    //head = animation->frames;
    newFrame->pNext = animation->frames;
    animation->frames = newFrame;

    /*while (head != NULL) {
        newFrame->pNext = *head;
        animation->frames = newFrame;
        printf("%s", *head->frameName);
        head = head->pNext;
    }*/

    //head = animation->frames;
    printf("\n");
}
}

void ReportAnimation(Animation* animation) {
printf("Animation name is Animation_1\n");
printf("Report the Animation\n");
struct Frame* head = animation->frames;
//printf("%s\n", head->frameName);

while (head) {
    printf("%s\n", head->frameName);
    head = head->pNext;
}
//printf("%d", count);
  }

Answer 1

至少函数InitAnimation没有意义

void InitAnimation(Animation* newAnimation) {
newAnimation = malloc(sizeof(Animation));
newAnimation->animationName = "Animation_1";
newAnimation->frames = NULL;
 }

因此整个程序是不正确的。

原始对象

Animation RG;
//...
InitAnimation(&RG);

未初始化。函数的参数只是被覆盖了。

由于定义，Animation 类型的对象已经在 main 中创建了

Animation RG;

你只需要初始化它的数据成员。

使用 malloc 调用删除语句

void InitAnimation(Animation* newAnimation) {
newAnimation->animationName = "Animation_1";
newAnimation->frames = NULL;
 }

通常你应该为数据成员animationName指向的字符串动态分配内存。

函数cam如下所示

int InitAnimation( Animation *newAnimation, const char *name ) 
{
    newAnimation->animationName = malloc( strlen( name ) + 1 );

    int success = newAnimation->animationName !+ NULL;

    if ( success )
    {
        strcpy( newAnimation->animationName, name );
        newAnimation->frames = NULL;
    }

    return success;
}

并像这样称呼

Animation RG;
//...
InitAnimation(&RG, "Animation_1" );

请注意，您需要在声明函数malloc 和free 的地方包含标题<stdlib.h>。