关于歌曲查找添加顺序列表c语言的程序

代码可以运行，但是程序无法使用求修改

/*-------------------------------------------------------------------------
    File Description: song list Algorithm with Sequential storage structure
    Author: liuxin_dz
   
-------------------------------------------------------------------------*/

#include
#include 
#include 

#define PRINT_NUM (10) //每次打印10个数据
#define ARRAY_SIZE (100)    //数组大小使用宏定义，数字使用括号括起
#define INVALID_FLAG (-1)    //无效标志
#define NULL ((void *)0) 

// 歌曲列表结构体定义
typedef struct tagSongList {
    int song_array[ARRAY_SIZE];    //数组存放歌曲号
    int song_numbers;    //歌曲总数
}SongList,*PSongList;

/*   I N I T   S O N G   L I S T   */
/*-------------------------------------------------------------------------
    Description: intiate song list 
    Input : ppSongList : the sencond level pointer 
    Result: void  
-------------------------------------------------------------------------*/
void initSongList(PSongList * ppSongList)
{
    int i = 0;
    assert(NULL != ppSongList);
    
    *ppSongList = NULL;
    PSongList pSongList = (PSongList)malloc(sizeof(SongList));
    if (NULL == pSongList)
        return;

    //初始化歌曲数组，全部为无效
    for (i = 0; i < ARRAY_SIZE; i++)
        pSongList->song_array[i] = INVALID_FLAG;
    pSongList->song_numbers = 0;
    
    *ppSongList = pSongList;
    return;
}

/*   D E S T R O Y   S O N G   L I S T   */
/*-------------------------------------------------------------------------
    Description: destroy song list 
    Input : pSongList : the pointer of the songlist 
    Result: void 
-------------------------------------------------------------------------*/
void destroySongList(PSongList pSongList)
{
    assert(NULL != pSongList);
    
    free(pSongList);
}

/*   S E A R C H   S O N G   */
/*-------------------------------------------------------------------------
    Description: search song 
    Input: PSongList pSongList: the song list, int song_id: the id of the song
            to be found
    Result: the positon of the song to be found in the array
            -1: search fail
            others: search success
-------------------------------------------------------------------------*/
int searchSong(PSongList pSongList, int song_id)
{
    int i = 0;

    assert(NULL != pSongList);

    for (i = 0;  ; i++){
        if ()    //歌曲编号查找成功
            return i;    //返回歌曲在数组中的位置
    }
    return -1;
}

/*   A D D   S O N G   */
/*-------------------------------------------------------------------------
    Description: add song 
    Input: PSongList pSongList: the song list, int song_id: the id of the song
            to be added
    Result: -1: add fail
            0: add success 
-------------------------------------------------------------------------*/
int addSong (PSongList pSongList, int song_id)
{
    assert(NULL != pSongList);

    int pos = searchSong(pSongList, song_id);
    if (-1 != pos){
        printf("歌曲%d已存在\r\n",song_id);
        return 0;
    }
    
    pos = searchSong(pSongList, INVALID_FLAG);
    if (-1 == pos)    //歌曲数组中没有空闲的位置
        return -1;    //添加失败 
    
    ;    //在该空闲位置存储歌曲号
    ;    //歌曲总数+1
    
    return 0;    //添加成功
}

/*   D E L E T E  S O N G   */
/*-------------------------------------------------------------------------
    Description: delete song 
    Input: PSongList pSongList: the song list, int song_id: the id of the song
            to be deleted
    Result: -1: delete fail
            0: delete success  
-------------------------------------------------------------------------*/
int deleteSong (PSongList pSongList, int song_id)
{
    assert(NULL != pSongList);

    int pos = searchSong(pSongList, song_id);
    if (-1 == pos)    //歌曲数组中没有待删除歌曲
        return -1;    //删除失败
    
    ;    //将歌曲所在位置元素置为无效标志
    ;    //歌曲总数-1
    
    return 0;    //删除成功
}

/*   P R I N T   L I S T   */
/*-------------------------------------------------------------------------
    Description: print song list , print 10 items in one time 
    Input: PSongList pSongList: the song list, int song_id: the id of the song
    Result: 
-------------------------------------------------------------------------*/
void printList(PSongList pSongList, int song_id)
{
    int start_print_pos = -1;
    int i = 0;

    assert(NULL != pSongList);

    int pos = searchSong(pSongList, song_id);
    if (-1 == pos)    //歌曲数组中没有待查找歌曲
        return;    //无需打印
    if (pos < PRINT_NUM/2)
        start_print_pos = 0;
    else if (pos > ARRAY_SIZE-PRINT_NUM/2)
        start_print_pos = ARRAY_SIZE-PRINT_NUM;
    else
        start_print_pos = pos - PRINT_NUM/2;
    
    //每次只打印待查歌曲前后总共10个元素的信息
    for (i = start_print_pos; i < (start_print_pos + PRINT_NUM); i++)
        printf("%3d    ",i);
    printf("\r\n");
    for (i = start_print_pos; i < (start_print_pos + PRINT_NUM); i++)
        printf("%3d    ",pSongList->song_array[i]);
    printf("\r\n");
    
}

int main()
{
    int choice;
    int song_id = -1;
    int rst = -1;
    PSongList pSongList = NULL;

    //初始化歌曲列表资源
    initSongList(&pSongList);

    while(1){
        printf("---------operations---------\r\n");
        printf("0:退出\r\n");
        printf("1:添加歌曲\r\n");
        printf("2:删除歌曲\r\n");
        printf("3:查找歌曲\r\n");

        scanf("%d", &choice);
        switch(choice ){
        case 1:
            printf("请输入待添加歌曲曲号\r\n");
            scanf("%d", &song_id);
            rst = addSong(pSongList, song_id);
            if (0 != rst)
                printf("歌曲%d添加失败\r\n",song_id);
            else
                printList(pSongList,song_id);
            break;
        case 2:
            printf("请输入待删除歌曲曲号\r\n");
            scanf("%d", &song_id);
            rst = deleteSong(pSongList, song_id);
            if (0 != rst)
                printf("歌曲%d删除失败\r\n",song_id);
            
            else
                printf("歌曲%d删除成功\r\n",song_id);
            break;
        case 3:
            printf("请输入待查找歌曲曲号\r\n");
            scanf("%d", &song_id);
            rst = searchSong(pSongList, song_id);
            if (-1 != rst){ 
                printf("歌曲%d查找成功\r\n",song_id);
                printList(pSongList,song_id);
            } 
            else
                printf("歌曲%d查找失败\r\n",song_id);
            break;
        case 0:
        default:
            destroySongList(pSongList);    //释放歌曲列表资源
            return 0;

        }
    }
}

代码76行这里的判断你没加条件，这样无法进行查找

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