diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/Array.h b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/Array.h
new file mode 100644
index 0000000..07918ce
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/Array.h	
@@ -0,0 +1,17 @@
+#ifndef _ARRAY_H_
+#define _ARRAY_H_
+
+#define BLOCK_SIZE 20
+
+typedef struct {
+	int* array;
+	int size;
+}Array;
+
+Array array_creat(int init_size);//初始化数组
+void array_free(Array* a);//释放堆上空间
+int array_size(const Array* a);//查看数组的大小
+int* array_at(Array* a, int index);
+void array_inflate(Array* a, int more_size);
+
+#endif
\ No newline at end of file
diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/main.c b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/main.c
new file mode 100644
index 0000000..b0cb754
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/01_Resizable Array/Func-Implementation/main.c	
@@ -0,0 +1,108 @@
+#define _CRT_SECURE_NO_WARNINGS 1
+
+#include"Array.h"
+#include<stdio.h>
+#include<stdlib.h>
+//typedef struct {
+//	int* array;
+//	int size;
+//}Array;
+
+Array array_creat(int init_size) {
+
+	Array a;
+
+	a.array = (int*)malloc(sizeof(int) * init_size);
+	a.size = init_size;
+
+	return a;
+}
+//为何不传入指针？
+//比如：Array array_creat(Array* a, int init_size)
+//问题如下：
+//1.如果a == NULL？
+//2.如果a指向的是已经malloc过的空间，那样还要再free一次
+
+void array_free(Array* a) {
+
+	free(a->array);
+	a->array = NULL;//防止此函数被调用两次。free(NULL)是可以的
+	a->size = 0;
+}
+
+int array_size(const Array* a) {
+
+	return a->size;
+}
+
+int* array_at(Array* a, int index) {
+
+	if (index >= a->size)
+		array_inflate(&a, (index / BLOCK_SIZE + 1) * BLOCK_SIZE - a->size);
+	//为什么不直接加上一个 BLOCK_SIZE？而是用 index / BLOCK_SIZE + 1) * BLOCK_SIZE - a->size) 这么复杂的公式？
+	//这样加强了程序的可变性，如果某一次数组增加的大小你不清楚，比如从 100 增加到 150
+	//直接加 BLOCL_SIZE 可能并不够用，用着个公式增加的大小一定 大于等于 需要增加的大小。
+	//为什么引入 BLOCKJ_SIZE ？
+	//一方面 增加了程序的扩展性（可以方便更改）和可读性，另一方面 
+	//如果你设置的 BLICK_SIZE 过大，数组大小这时就增加 1，这样太浪费内存
+	//如果设置的过小就不能数组满足大幅的更改
+	//拿本题 BLOCK_SIZE = 20 为例，一次最多多增加 19 个 int 的大小，这也就意味着
+	//这种方法浪费的内存最多只有 19*sizeof(int) 个字节
+
+	return &(a->array[index]);
+}
+
+////输出数组元素
+//int array_get(const Array a, int index) {
+//
+//	return a.array[index];
+//}
+////修改数组元素
+//int array_set(Array* a, int index, int value) {
+//	
+//	return (a->array[index] = value);
+//}
+
+void array_inflate(Array* a, int more_size) {
+
+	int* p = (int*)malloc(sizeof(int) * (a->size + more_size));
+	int i = 0;
+
+	//可换成memcpy
+	for (i = 0; i < a->size; i++) {
+		p[i] = a->array[i];
+	}
+	free(a->array);
+
+	a->array = p;
+	a->size += more_size;
+}
+
+
+int main(void) {
+
+	Array a;
+	int size = 0;
+
+	printf("初始化数组大小,请输入：\n");
+	scanf("%d", &size);
+
+	a = array_creat(size);
+
+	printf("%d members in array\n", array_size(&a));
+	//为什么不直接用 a.size 输出数组的大小？
+	//这样用函数来返回数组大小的方式就叫做 封装
+	//日后如果有版本更新，算法优化等等，可以用函数来实现，将实现的代码保护起来
+
+	//array_at(&a, 1) 返回 &(a.array[1]) 解引用即使这个变量 array[1]
+	//当然这个函数可以拆开，实现在array_at 后
+	*array_at(&a, 1) = 10;
+	printf("a.array[1] = %d\n", *array_at(&a, 1));
+
+
+	return 0;
+}
+
+
+
+
diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/LinkedList.h b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/LinkedList.h
new file mode 100644
index 0000000..05046ca
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/LinkedList.h	
@@ -0,0 +1,13 @@
+#ifndef _LINK_LIST_
+#define _LINK_LIST_
+
+typedef struct _node {
+
+	char Name[20];
+	char Gender[5];
+	int Age;
+	long long ID;
+	struct _node* next;
+}node;
+
+#endif
\ No newline at end of file
diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/main.c b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/main.c
new file mode 100644
index 0000000..66d6ab4
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/main.c	
@@ -0,0 +1,59 @@
+#define _CRT_SECURE_NO_WARNINGS 1
+
+#include<stdio.h>
+#include<stdlib.h>
+#include"Array.h"
+
+//typedef struct _node {
+//
+//	char name[20];
+//	char gender[5];
+//	int age;
+//	long long ID;
+//}node;
+
+int main(void) {
+
+	node* head = NULL;
+	int count = 1;
+	int Exit = 0;
+
+	do {
+		printf("是否继续？输入 0 退出\n");
+		scanf("%d", &Exit);
+
+		if (Exit) {
+			printf("请输入第 %d 个学生信息\n", count++);
+			node* p = (node*)malloc(sizeof(node));
+			printf("\t\t姓名: ");
+			scanf("%s", p->Name);
+			printf("\t\t性别: ");
+			scanf("%s", p->Gender);
+			printf("\t\t年龄: ");
+			scanf("%d", &(p->Age));
+			printf("\t\t学号: ");
+			scanf("%lld", &(p->ID));
+
+			p->next = NULL;
+
+			node* last = head;//创建新的节点需要寻找最后一个放 NULL 的节点
+
+			//如果表头是空指针
+			if (last) {
+				//节点 指针域为NULL 找到了
+				while (last->next)
+					last = last->next;
+				last->next = p;
+			}
+			else
+				head = p;
+		}
+	} while (Exit);
+
+
+	return 0;
+}
+
+
+
+
diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/readme.md b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/readme.md
new file mode 100644
index 0000000..8847f8a
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/02_linked list basis/01 in main/readme.md	
@@ -0,0 +1,3 @@
+缈佹伜MOOC
+
+main 鍑芥暟涓殑閾捐〃鍒涘缓
\ No newline at end of file
diff --git a/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/readme.md b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/readme.md
new file mode 100644
index 0000000..03b2387
--- /dev/null
+++ b/C Crash Course/17 Advanced Pointer/02 Linked List/prelesson/WengKai MOOC/readme.md	
@@ -0,0 +1,2 @@
+缈佹伜鑰佸笀 MOOC
+
diff --git a/C Crash Course/21 Input&Output/prelesson/test code/test.c b/C Crash Course/21 Input&Output/prelesson/test code/test.c
new file mode 100644
index 0000000..4a2b4f5
--- /dev/null
+++ b/C Crash Course/21 Input&Output/prelesson/test code/test.c	
@@ -0,0 +1,195 @@
+#include<stdio.h>
+
+int main(void) {
+
+	printf("%+09d\n", 123);
+	printf("%-+09d\n", -123);
+	return 0;
+}
+
+int main(void) {
+
+	printf("%+09.2f\n", 12.3);
+	printf("%-8.3f\n", -12.3);
+	return 0;
+}
+
+int main(void) {
+
+	int len = 5;
+	int dec = 2;
+	printf("%*.*f\n",5, 2, 12.3);
+	printf("%*.*f\n",len, dec, 12.3);
+	return 0;
+}
+
+int main(void) {
+
+	printf("%hhd\n", (char)12345);//当作 1 个字节输出
+	printf("%hd\n", 12345);//当作 short 输出
+	return 0;
+}
+
+int main() {
+
+	int num;
+	printf("%d%n\n", 123, &num);
+	printf("%d\n", num);
+
+	return 0;
+}
+
+int main() {
+
+	int num;
+	scanf("%*d %d", &num);
+	printf("%d\n", num);
+
+	return 0;
+}
+
+int main(void) {
+	
+	float x;
+	scanf("%g", &x);
+	printf("%F", x);
+	
+	return 0;
+}
+
+int main(void) {
+
+	int num = 0;
+	int return_scanf = 0;
+	int return_printf = 0;
+
+	return_scanf = scanf("%d", &num);
+	return_printf = printf("%d\n", num);
+
+	printf("%d:%d\n", return_scanf, return_printf);
+	return 0;
+}
+
+
+FILE* fp = fopen("file", "r");
+
+if (fp) {
+	fscanf(fp, ...);
+	fclose(fp);
+}
+else {
+	...
+}
+
+#include<stdio.h>
+#include<stdlib.h>
+#include "student.h"
+
+void getList(Student* Stu, int num);
+int save(Student* Stu, int num);
+
+int main(void) {
+
+	int num = 0;
+	
+	printf("请输入学生数量：\n");
+	scanf("%d", &num);
+	Student* Stu = (Student*)malloc(sizeof(Student) * num);
+
+	getList(Stu, num);
+	
+	if (save(Stu, num)) {
+		printf("保存成功\n");
+	}
+	else
+		printf("保存失败\n");
+
+	return 0;
+}
+
+void getList(Student* Stu, int num) {
+
+	char format[STR_LEN];
+	sprintf(format, "%%%ds", STR_LEN - 1);
+	//向 format 中写入 %19s
+	//%%%ds 前两个%的意义是写入% 
+	//%d 输出后面的参数，即：19 
+	//最终写入的就是 %19s
+
+	int i = 0;
+
+	for (i = 0; i < num; i++) {
+
+		printf("第 %d 个学生 \n", i + 1);
+		printf("\t姓名：");
+		scanf(format, Stu[i].name);
+		printf("\t性别（0-男 1-女 2-其他）:");
+		scanf("%d", &Stu[i].gender);
+		printf("\t年龄:");
+		scanf("%d", &Stu[i].age);
+		//记得用scanf时，何时用 & 
+	}
+
+}
+
+int save(Student* Stu, int num) {
+
+	int ret = -1;
+	FILE* fp = fopen("student.data", "w");
+	if (fp) {
+		ret = fwrite(Stu, sizeof(Student), num, fp);
+		//记录 fwrite 的返回值：写入文件的学生个数
+		fclose(fp);
+	}
+	else
+		printf("文件打开失败！");
+
+	return (ret == num);
+	//如果写入的个数不等于总人数，返回0
+}
+
+#include<stdio.h>
+#include"student.h"
+
+void read(FILE* fp, int index);
+
+int main(void) {
+
+	FILE* fp = fopen("student.data", "r");
+	if (fp) {
+		fseek(fp, 0L, SEEK_END);//将文件读/写开始的位置定到结尾
+		long size = ftell(fp);//获得从文件开始到文件结尾的字节数
+		int index = 0;
+		int number = size / sizeof(Student);
+		printf("有 %d 个学生数据，你要看第几个\n", number);
+		scanf("%d", &index);
+		read(fp, index - 1);
+	}
+	else
+		printf("文件打开失败！\n");
+}
+
+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：\n", 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;
+		default:
+			printf("其他\n");
+			break;
+		}
+		printf("\t年龄：%d\n", stu.age);
+	}
+}
\ No newline at end of file