将行从文件复制到 char *array[]?

Question

您好，需要一点帮助。我有一个包含 5 行的文件，我想将这些行放入 char *lines[5]; 类型的数组中，但我无法弄清楚为什么以下内容不起作用。

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

int main(void) {
    FILE *fp = fopen("name.txt", "r");
    char *str;
    char *list[5];
    int i = 0;

    while (fgets(str, 100, fp) != NULL) // read line of text
    {
        printf("%s", str);
        strcpy(list[i], str);
        i++;
    } 
}

Answer 1

正如评论者所说，您需要创建一个足够大的数组（只不过是内存中的 space）来存储您的字符串。解决问题的一种方法如下，请注意评论：

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

    int lines(FILE *file); //try to format the code according to some standard
    int main(void) {
        FILE *fp = fopen("name.txt", "r");
        char list[5][100]; //make sure you allocate enough space for your message

// for loop is more elegant than while loop in this case, 
// as you have an index which increases anyway.
// also, you can make sure that files with more than 5 lines 
// do not break your program.
        for(int i = 0; i<5 ;++i ) 
        {
            if(fgets(list[i], 100, fp) == NULL){
               break;
            }
            //list[i] is already a string, you don't need an extra copy
            printf("%s", list[i]);
        } 
    }

将行从文件复制到 char *array[]?

Copy lines from file to char *array[]?

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