C语言 二进制文件-代码记录

一、二进制文件写入

#include 
#include 
#include "student.h"

void getList(Student aStu[], int number);
int save(Student aStu[], int number);

int main(int argc, char const *argv[]) {
	int number = 0;
	printf("输入学生数量：");
	scanf_s("%d", &number);
	Student* aStu = (Student*)malloc(sizeof(Student) * number);

	getList(aStu, number);
	if (save(aStu, number)) {
		printf("保存成功\n");
	}
	else {
		printf("保存失败\n");
	}

	free(aStu);
	return 0;
}

void getList(Student aStu[], int number) {
	char format[STR_LEN];
	sprintf_s(format, "%%%ds", STR_LEN - 1);

	int i;
	for (i = 0; i < number; i++) {
		printf("第%d个学生:\n", i);
		printf("\t姓名：");
		scanf_s(format, &aStu[i].name, STR_LEN);
		printf("\t性别（0-男，1-女，2-其他）：");
		scanf_s("%d", &aStu[i].gender);
		printf("\t年龄：");
		scanf_s("%d", &aStu[i].age);
	}
}

int save(Student aStu[], int number) {
	int ret = -1;
	FILE* fp;
	fopen_s(&fp, "student.data", "w");
	if (fp) {
		ret = fwrite(aStu, sizeof(Student), number, fp);
		fclose(fp);
	}
	return ret == number;
}

student.h

const int STR_LEN = 20;

typedef struct _student {
	char name[STR_LEN];
	int gender;
	int age;
} Student;

二、二进制文件读取

#include 
#include "student.h"

void read(FILE* fp, int index);

int main(int argc, char const* argv[]) {
	FILE* fp;
	fopen_s(&fp, "student.data", "r");
	if (fp) {
		fseek(fp, 0L, SEEK_END);
		long size = ftell(fp);
		int number = size / sizeof(Student);
		int index = 0;
		printf("有%d个数据， 你要看第几个：", number);
		scanf_s("%d", &index);
		read(fp, index - 1);
		fclose(fp);
	}
	return 0;
}

void read(FILE* fp, int index) {
	fseek(fp, index * sizeof(Student), SEEK_SET);
	Student stu;
	if (fread(&stu, sizeof(Student), 1, fp) == 1) {
		printf("第%d个学生：", index + 1);
		printf("\t姓名：%s\n", stu.name);
		printf("\t性别：");
		switch (stu.gender) {
		    case 0: printf("男\n"); break;
			case 1: printf("女\n"); break;
			case 2: printf("其他\n"); break;
		}
		printf("\t年龄：%d\n", stu.age);
	}
}

student.h 同一