.c file I/O studentDB.bin

#include<stdio.h>
#define _CRT_SECURE_NO_WARNINGS
#include<string.h>
#define max_num_student 255

enum action {add, fine, Exit};
typedef struct {
	int id;
	char name[8];
	float score;
}student;

int fileopen(FILE** _fp, char* _filename, char* _mode);
int selectaction(void);
int printinfo(student* _info);
int addstudent(FILE* _fp, student* _info);
long finestudent(FILE* _fp, student* _info);

int main(void)
{
	FILE* fp = NULL;
	student data = { 0 };
	char* filename = "studentDB.bin";
	fileopen(&fp, filename, "ab+");

	while (1)
	{
		switch (selectaction())
		{
		case add:
			addstudent(fp, &data);
			break;
		case fine:
			if (finestudent(fp, &data) < 0)
				printf("Can not fine the student\n");
			else
				printinfo(&data);
			break;
		case Exit:
			exit(0);

		}
	}
}

int selectaction(void)
{
	int sel = 0;
	printf("[%d]add, [%d]find, [%d]exit: ", add, fine, Exit);
	scanf("%d", &sel);
	return sel;
}

int printinfo(student* _info)
{
	printf("%d %s %.2f\n", _info->id, _info->name, _info->score);
}

int addstudent(FILE* _fp, student* _info)
{
	printf("Enter id name score : ");
	scanf("%d %s %f", &_info->id, &_info->name, &_info->score); getchar();

	fseek(_fp, 0, SEEK_END);
	fwrite(_info, sizeof(student), 1, _fp);
	return 0;
}

long finestudent(FILE* fp, student* info)
{
	char name[255] = { 0 };
	printf("name: ");
	scanf("%s", name); getchar();

	//file pointer 처음으로 돌림.
	fseek(fp, 0, SEEK_SET);
	//size 선언 안 하고 진행하니 error 발생. sizeof 함수가 unsigned int type인데 -붙여서 conversion 일어남.
	int size = sizeof(student);
	while (!feof(fp))
	{
		fread(info, size, 1, fp);
		if (strcmp(info->name, name) == 0) {
			fseek(fp, -size, SEEK_CUR);
			return ftell(fp);
		}
	}
	return -1;
}

int fileopen(FILE** _fp, char* _fileName, char* _mode)
{
	*_fp = fopen(_fileName, _mode);
	if (!*_fp) {
		printf("Fail to open - %s\n", _fileName);
		return -1;
	}
	return 0;
}

fseek에 -sizeof(student)를 argument로 전달했는데 sizeof가 unsigned int 이기 때문에 -를 붙일 수가 없음.