c - 在 C 中使用 scanf 读取直到破折号

Question

我正在尝试将歌曲读入 C 中的字符串变量。我使用破折号(“-”)来区分艺术家和歌曲。这是程序:

#include <stdio.h>

int main() {
    char *artist, *song;
    printf("Please copy all of the songs you wish to download below.\n");
    printf("When you have finished, please input a full stop.\n\n");
    scanf("%[^-] %s", artist, song);
    printf("%s %s\n", artist, song);
    return 0;
}

当我使用这个程序时，例如输入“艺术家-歌曲”，输出如下:

Please copy all of the songs you wish to download below.
When you have finished, please input a full stop.

artist - song
artist  (null)

我试过使用 scanf("%[^-] %[^\n]", artist, song); 结果是一样的。

我怎样才能读取破折号后的所有内容？

Answer 1

artist 和song 是指针。他们没有指向任何有效的地方。在将它们指向有效位置之前，您不能使用它们。

尝试使用数组。

#include <stdio.h>

int main(void) {
    char artist[100], song[100]; // arrays, not pointers
    printf("Please copy all of the songs you wish to download below.\n");
    printf("When you have finished, please input a full stop.\n\n");
    if (scanf("%99[^-]-%99s", artist, song) != 2) /* error */;
    printf("%s %s\n", artist, song);
    return 0;
}

或者，如果你想使用指针，在输入之前为它们分配内存

#include <stdio.h> /* printf(), scanf() */
#include <stdlib.h> /* malloc(), free() */

int main(void) {
    char *artist, *song;
    artist = malloc(100);
    if (!artist) /* error */;
    song = malloc(100);
    if (!song) /* error */;
    printf("Please copy all of the songs you wish to download below.\n");
    printf("When you have finished, please input a full stop.\n\n");
    if (scanf("%99[^-]-%99s", artist, song) != 2) /* error */;
    printf("%s %s\n", artist, song);
    free(song);
    free(artist);
    return 0;
}