c - 将结构数组写入 C 中的二进制文件

Question

我有一个结构数组，我想写入一个二进制文件。我有一个 write.c 程序和一个 read.c 程序。 write.c 程序似乎工作正常，但是当我运行 read.c 程序时，出现段错误。我是 C 的新手，所以如果有人可以检查我的代码是否有任何明显的错误，那就太好了。我保证不会太长:)

写.c:

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

struct Person 
{
    char f_name[256];
    char l_name[256];
    int age;
};

int main(int argc, char* argv[])
{
    struct Person* people;
    int people_count;

    printf("How many people would you like to create: ");
    scanf("%i", &people_count);
    people = malloc(sizeof(struct Person) * people_count);  

    int n;
    for (n = 0; n < people_count; n++)
    {
        printf("Person %i's First Name: ", n);
        scanf("%s", people[n].f_name);

        printf("Person %i's Last Name: ", n);
        scanf("%s", people[n].l_name);

        printf("Person %i's Age: ", n);
        scanf("%i", &people[n].age);
    }

    FILE* data;
    if ( (data = fopen("data.bin", "wb")) == NULL )
    {
        printf("Error opening file\n");
        return 1;   
    }

    fwrite(people, sizeof(struct Person) * people_count, 1, data);
    fclose(data);

    return 0;
}

读.c:

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

struct Person 
{
    char f_name[256];
    char l_name[256];
    int age;
};

int main(int argc, char* argv[])
{
    FILE* data;
    if ((data = fopen("data.bin", "rb")) == NULL)
    {
        printf("Error opening file\n");
        return 1;
    }

    struct Person* people;

    fread(people, sizeof(struct Person) * 1/* Just read one person */, 1, data);
    printf("%s\n", people[0].f_name);

    fclose(data);

    return 0;
}

感谢您的帮助!

Answer 1

struct Person* people;

这只分配了一个指向结构的指针，但您没有为实际结构内容分配任何空间。要么像您的写入程序一样使用 malloc，要么尝试类似的方法:

struct Person people;
fread(&people, sizeof(people), 1, data);