c-传递strcpy的参数2使指针从integer变为不带强制转换

Question

这是我所做的全部代码，我试图创建一个歌曲库，将用户输入的内容放入文件中。现在编译器说，传递strcpy的参数2会使指针从integer变成不带强制转换的指针，我不知道为什么。你也可以检查我的链表中的结构。我不在链接列表中：（

#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("%dn", &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。它应该是

    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。从未初始化的变量中读取是未绑定的行为。

您可能面临的另一个问题是，如果有可用空间，fgets()会将新行n读取到缓冲区中，这可能会有问题。需要注意的事项，必要时需要修剪。

Answer 2

这是您代码的工作副本，除了一件事"Remark"。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，constchar*src）。所以我相应地改变了

#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("%dn", &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;
}

Answer 3

没有遍历整个代码，但strcpy问题很明显。根据函数strcpy的定义(http://www.tutorialspoint.com/c_standard_library/c_function_strcpy.htm)，它需要两个字符指针（即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，它不是指针。更改函数add_song的签名，然后您应该可以使用strcpy