传递 strcpy 的参数 2 使指针来自整数而不进行强制转换

Question

这是我正在做的全部代码，我正在尝试创建一个歌曲库，将用户输入的内容放入文件中。现在编译器说传递参数 2 的 strcpy 使指针来自整数而不进行强制转换，我不知道为什么。你也可以检查我的链接列表中的结构。我在链表上很菜鸟:(

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

struct node {
    //definition of struct node to create struct node song
    int SongID;
    char Title[100];
    char Artist[100];
    char Composer[100];
    char Album[100];
    char Genre[100];
    int Rating;
    char Remarks[1000];
    struct node*next;
};

add_song(int SongID, char Title, char Artist, char Composer, char Album, char Genre, int Rating, char Remarks) {
    //this is the add song function as stated in the mp2 specs
    FILE*fp;
    fp=fopen("song.txt","r+");

    int i=1, j, choice;
    struct node* temp=malloc(sizeof(struct node));

    temp->SongID=SongID;
    fprintf(fp,"%d",SongID);

    strcpy(temp->Title, Title);
    fprintf(fp,"%s",Title);

    strcpy(temp->Artist, Artist);
    fprintf(fp,"%s",Artist);

    strcpy(temp->Composer, Composer);
    fprintf(fp,"%s",Composer);

    strcpy(temp->Album, Album);
    fprintf(fp,"%s",Album);

    strcpy(temp->Genre, Genre);
    fprintf(fp,"%s",Genre);

    temp->Rating=Rating;
    fprintf(fp,"%d",Rating);

    strcpy(temp->Remarks, Remarks);
    fprintf(fp,"%s",Remarks);

    fclose(fp);
}

int main ()
{
    struct node song;
    int choice;
    int k, i;
    int SongID;
    char Title[100];
    char Artist[100];
    char Composer[100];
    char Album[100];
    char Genre[100];
    int Rating;
    char Remarks[1000];

   /* do
     {
        printf("Enter 1 to add song, 2 to update song, or 3 to list songs: ");
        scanf("%d\n", &choice1);

        if (choice1==1)
        {*/
        srand(time(NULL));
        song.SongID=rand();

        printf("Enter Title: ");
        fgets(Title,100,stdin);

        printf("Enter Artist: ");
        fgets(Artist,100,stdin);

        printf("Enter Composer: ");
        fgets(Composer,100,stdin);

        printf("Enter Album: ");
        fgets(Album,100,stdin);

        //for easier code, numbers are being chosen as input
        printf("Press 1 for Art Music, 2 for Popular Music, or 3 for Traditional Music): ");
        scanf("%d", &choice);

        if (choice==1)
        {
            strcpy(song.Genre,"Art Music");
        }
        else if (choice==2)
        {
            strcpy(song.Genre,"Popular Music");
        }
        else if (choice==3)
        {
            strcpy(song.Genre,"Traditional Music");
        }
        else
        {
            printf("You entered a blank genre.\n");
        }

        printf("Enter your rating, choose from 1-5: ");
        scanf("%d", &Rating);

        printf("Enter Remarks: ");
        fgets(Remarks,1000,stdin);

        add_song(SongID, Title, Artist, Composer, Album, Genre, Rating, Remarks);
            /*k=0;
            break;
        }
        else if (choice1==2)
        {
            //update_song(song);
            k=0;
            break;
        }
        else if (choice1==3)
        {
           // list_songs(song);
            k=0;
            break;
        }
        else
        {
            k=1;
            printf("That is not a valid input.\n");
        }
    }while (k==1);*/

    return 0;
}

Answer 1

您的函数定义与您传递的参数不匹配。应该是

    void add_song(int SongID, char *Title, char *Artist, char *Composer, \
char *Album, char *Genre, int Rating, char *Remarks) {

       ...
       ...
    }

另一个问题是 songID 在 main() 中未初始化。从未初始化的变量读取是 undefind behaviour.

您可能面临的另一个问题是，如果 space 可用，fgets() 会将换行符 \n 读入缓冲区，这可能会出现问题。需要注意的事项，如果需要，您需要 trim。

Answer 2

没有遍历整个代码，但是strcpy问题很明显。根据函数 strcpy (http://www.tutorialspoint.com/c_standard_library/c_function_strcpy.htm) 的定义，它需要两个字符指针（也就是 C 中的字符串）

char *strcpy(char *dest, const char *src)

您只将 char 参数传递给函数 add_song，这不是指针。更改函数的签名 add_song 然后你应该可以使用 strcpy

Answer 3

除了一件事 "Remark"，这是您代码的工作副本。在执行 scanf for Remark 之前进程退出。像我在这里所做的那样更改您的参数，并将 fopen 模式更改为 +w，这样如果文件不存在，它可以自动创建。 strcpy 原型是 `char *strcpy(char *dest, const char *src)。所以我做了相应的改变

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

struct node {
    //definition of struct node to create struct node song
    int SongID;
    char Title[100];
    char Artist[100];
    char Composer[100];
    char Album[100];
    char Genre[100];
    int Rating;
    char Remarks[1000];
    struct node *next;
};

void add_song(int SongID, char *Title, char *Artist, char *Composer, char *Album, char *Genre, int Rating, char *Remarks) {

    //this is the add song function as stated in the mp2 specs
    FILE *fp;
    fp=fopen("song.txt","a+");

    int i=1, j, choice;
    struct node* temp=malloc(sizeof(struct node));

    temp->SongID=SongID;
    fprintf(fp,"%d",SongID);

    strcpy(temp->Title, Title);
    fprintf(fp,"%s",Title);

    strcpy(temp->Artist, Artist);
    fprintf(fp,"%s",Artist);

    strcpy(temp->Composer, Composer);
    fprintf(fp,"%s",Composer);

    strcpy(temp->Album, Album);
    fprintf(fp,"%s",Album);

    strcpy(temp->Genre, Genre);
    fprintf(fp,"%s",Genre);

    temp->Rating=Rating;
    fprintf(fp,"%d",Rating);

    strcpy(temp->Remarks, Remarks);
    fprintf(fp,"%s",Remarks);

    fclose(fp);
}

int main ()
{
    struct node song;
    int choice;
    int k, i;
    int SongID;
    char Title[100];
    char Artist[100];
    char Composer[100];
    char Album[100];
    char Genre[100];
    int Rating;
    char Remarks[1000];

   /* do
     {
        printf("Enter 1 to add song, 2 to update song, or 3 to list songs: ");
        scanf("%d\n", &choice1);

        if (choice1==1)
        {*/
        srand(time(NULL));
        song.SongID=rand();

        printf("Enter Title: ");
        fgets(Title,100,stdin);

        printf("Enter Artist: ");
        fgets(Artist,100,stdin);

        printf("Enter Composer: ");
        fgets(Composer,100,stdin);

        printf("Enter Album: ");
        fgets(Album,100,stdin);

        //for easier code, numbers are being chosen as input
        printf("Press 1 for Art Music, 2 for Popular Music, or 3 for Traditional Music): ");
        scanf("%d", &choice);

        if (choice==1)
        {

            strcpy(song.Genre,"Art Music");
        }
        else if (choice==2)
        {

             strcpy(song.Genre,"Popular Music");
        }
        else if (choice==3)
        {

            strcpy(song.Genre,"Traditional Music");
        }
        else
        {
            printf("You entered a blank genre.\n");
        }

        printf("Enter your rating, choose from 1-5: ");
        scanf("%d",&Rating);

        printf("Enter Remarks: \n");
        fgets(Remarks,1000,stdin);

        add_song(SongID, Title, Artist, Composer, Album, Genre, Rating, Remarks);
            /*k=0;
            break;
        }
        else if (choice1==2)
        {
            //update_song(song);
            k=0;
            break;
        }
        else if (choice1==3)
        {
           // list_songs(song);
            k=0;
            break;
        }
        else
        {
            k=1;
            printf("That is not a valid input.\n");
        }
    }while (k==1);*/

    return 0;
}

传递 strcpy 的参数 2 使指针来自整数而不进行强制转换

passing argument 2 of strcpy makes pointer from integer without a cast

c

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