C语言读取预约数据文件失败：代码报错求助

问题描述 #

编写了一段C语言代码，意图读取appointmentData.txt文本文件中的预约数据并存储到对应变量，但代码无法读取文件。已排查文件路径、拼写等问题仍未解决，附上代码及待读取文本内容，请求指出错误。

我的代码 #

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

#define MAX_APPOINTMENTS 50

int main(){

     int appointmentCount = importAppointments("appointmentData.txt", appoints, MAX_APPOINTMENTS);
     printf("Imported %d appointment records...\n", appointmentCount);

     return 0;

}

int importAppointments(char *filename, struct Appointment appoints[], int max){
    
    FILE* file = fopen(filename, "r");
    
    int i=0;
    char ch;
    if (file != NULL)
    {

        while (i < max && fscanf(file, "%d,%d,%d,%d,%d,%d%c",
              &appoints[i].patientNumber, &appoints[i].date.year, &appoints[i].date.month,
              &appoints[i].date.day, &appoints[i].time.hour, &appoints[i].time.min, &ch) == 7)
        {

            if(ch != '\n')
            {
                while(fgetc(file) != '\n');
            }
        
            i++;
        }
        
        
        fclose(file);
        file = NULL;
    }else{

        printf("Error opening file: %s\n", filename);
        return 0;
    }
    
    
    return i;
}

待读取的文本内容 #

1040,2024,2,29,13,0
1112,2027,3,12,13,0
1048,2026,6,20,10,30
1080,2024,2,29,10,30
1104,2026,6,9,14,0
1088,2024,2,29,11,30
1104,2024,2,29,14,0
1112,2024,2,29,12,0
1056,2025,2,28,11,30
1024,2024,2,29,10,0
1032,2024,2,29,13,30
1120,2024,2,29,11,0
1112,2027,3,10,11,0
1128,2024,2,29,12,30
1024,2027,3,12,10,30

错误分析与修复方案 #

1. 缺失结构体定义 #

代码中使用了struct Appointment、appoints[i].date、appoints[i].time，但未定义这些结构体，编译器无法识别类型，直接编译失败。需补充定义：

// 日期结构体
struct Date {
    int year;
    int month;
    int day;
};

// 时间结构体
struct Time {
    int hour;
    int min;
};

// 预约结构体
struct Appointment {
    int patientNumber;
    struct Date date;
    struct Time time;
};

将这段代码放在#define MAX_APPOINTMENTS 50之后、main函数之前。

2. 未声明appoints变量 #

main函数中直接使用appoints作为参数，但未定义该变量。需在main内添加：

struct Appointment appoints[MAX_APPOINTMENTS];

3. 缺失函数声明 #

importAppointments函数在main之后定义，main调用前未声明，会导致编译器参数类型匹配错误。需在main前添加函数声明：

int importAppointments(char *filename, struct Appointment appoints[], int max);

4. fscanf格式串的潜在问题 #

原格式串%d,%d,%d,%d,%d,%d%c依赖最后一个字符是换行符，若文件最后一行无换行符会读取失败。更稳妥的方式是读取6个整数后跳过剩余行内容：

while (i < max && fscanf(file, "%d,%d,%d,%d,%d,%d",
      &appoints[i].patientNumber, &appoints[i].date.year, &appoints[i].date.month,
      &appoints[i].date.day, &appoints[i].time.hour, &appoints[i].time.min) == 6)
{
    // 跳过当前行剩余字符（含换行）
    int c;
    while ((c = fgetc(file)) != '\n' && c != EOF);
    i++;
}

5. 文件打开失败的返回值歧义 #

原代码打开失败返回0，与读取0条记录的返回值混淆，可改为返回-1标识打开失败，main中做判断：

// importAppointments错误分支
printf("Error opening file: %s\n", filename);
return -1;

// main中调用逻辑
int appointmentCount = importAppointments("appointmentData.txt", appoints, MAX_APPOINTMENTS);
if (appointmentCount == -1) {
    return 1;
}

修复后的完整代码 #

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

#define MAX_APPOINTMENTS 50

// 定义日期结构体
struct Date {
    int year;
    int month;
    int day;
};

// 定义时间结构体
struct Time {
    int hour;
    int min;
};

// 定义预约结构体
struct Appointment {
    int patientNumber;
    struct Date date;
    struct Time time;
};

// 函数声明
int importAppointments(char *filename, struct Appointment appoints[], int max);

int main(){
    struct Appointment appoints[MAX_APPOINTMENTS];
    int appointmentCount = importAppointments("appointmentData.txt", appoints, MAX_APPOINTMENTS);
    
    if (appointmentCount == -1) {
        return 1;
    }
    
    printf("Imported %d appointment records...\n", appointmentCount);

    return 0;
}

int importAppointments(char *filename, struct Appointment appoints[], int max){
    FILE* file = fopen(filename, "r");
    
    int i=0;
    if (file != NULL)
    {
        while (i < max && fscanf(file, "%d,%d,%d,%d,%d,%d",
              &appoints[i].patientNumber, &appoints[i].date.year, &appoints[i].date.month,
              &appoints[i].date.day, &appoints[i].time.hour, &appoints[i].time.min) == 6)
        {
            // 跳过当前行剩余字符
            int c;
            while ((c = fgetc(file)) != '\n' && c != EOF);
            i++;
        }
        
        fclose(file);
    }else{
        printf("Error opening file: %s\n", filename);
        return -1;
    }
    
    return i;
}

内容的提问来源于stack exchange，提问作者awnia