Question

我正在为某个程序编写C代码以模拟患者数据库。我设法编写了将患者添加到数据库并将信息保存到文本文件的代码。

下面关闭数据库的代码并将信息保存到文本文件的代码很正常：

FILE *close_file;

close_file = fopen(file_name, "w");

if (close_file == NULL){
printf("save information to file failed!\n");
fclose(close_file);
exit(EXIT_FAILURE);
}

fprintf(close_file, "%d\n", *num_of_structs);/*Enters the number of the 
                                               patient in the DB in the 
                                              beginning of the text file*/

for (int j = 0; j < *num_of_structs;j++){

/*the for loop down below is to write referens number to the patients x- 
ray pictures, so the first two numbers in the text file belong to an array 
of two rooms*/

for (int picture = 0; picture < 2; picture++){
fprintf(close_file, "%d ", patientRegister[j].pictures[picture]);
}

/*down below I write the personal number and the name of the patient to 
the text file*/

fprintf(close_file, "%d %s", patientRegister[j].personal_number, 
patientRegister[j].patient_name);

}

fclose(close_file);

}

文本文件如下所示： https://ibb.co/FKdx4vg

我的问题是如何从此文本文件读取？我尝试了很多代码，但没有成功。看到我的代码对我来说不起作用，除了以下行：

fscanf(existing_file, "%d", num_of_structs);/*This reads the first number 
at the top of the text file and which represents the number of patients in 
the DB*/

查看应该打开一个文本文件并从中读取的整个功能：

void open_existing_file(Patient patientRegister[], char file_name[], int 
*num_of_structs) {

FILE *existing_file;

existing_file = fopen(file_name, "r");

if (existing_file == NULL) {
printf("Open existing file failed\n");
fclose(existing_file);
exit(EXIT_FAILURE);
}


fscanf(existing_file, "%d", num_of_structs);/*This reads the first number 
at the top of the text file and which represents the number of patients in 
the DB*/

/*I guess I'm doing a lot of wrong code down here?!*/

for (int j = 0; j < (*num_of_structs); j++) {

for (int picture = 0; picture < 2; picture++) {
fscanf(existing_file, "%d", patientRegister[j].pictures[picture]);
}

fscanf(existing_file, "%d %s", patientRegister[j].personal_number, 
patientRegister[j].patient_name);}

fclose(existing_file);
}

Answer 1

SELECT Name, STUFF((SELECT DISTINCT ',' + Number FROM BSFolks WHERE Name = X.Name AND (Number != '' AND Number IS NOT NULL) FOR XML PATH ('')), 1, 1, '') AS Numbers FROM BSFolks X GROUP BY Name的{{1}}格式说明符期望%d的地址，即scanf，而不是int 。这样就可以将读取的值写入变量。

所以你想要

int *

请注意，int不需要fscanf(existing_file, "%d", &num_of_structs); ... fscanf(existing_file, "%d", &patientRegister[j].pictures[picture]); ... fscanf(existing_file, "%d %s", &patientRegister[j].personal_number, patientRegister[j].patient_name);即可读入数组，因为数组会自动衰减为指向其第一个元素的指针。

如何从我创建的文本文件中读取结构？

1 个答案: