diff --git a/C Crash Course/16 Sturcture&Union&Enum/stucture/prelesson/test/test.c b/C Crash Course/16 Sturcture&Union&Enum/stucture/prelesson/test/test.c
new file mode 100644
index 0000000..972550f
--- /dev/null
+++ b/C Crash Course/16 Sturcture&Union&Enum/stucture/prelesson/test/test.c	
@@ -0,0 +1,542 @@
+#define _CRT_SECURE_NO_WARNINGS 1
+
+enum color {
+	red, yellow, blue
+};
+
+#include<stdio.h>
+
+enum color {
+	red, yellow, blue
+};
+
+void f(enum color x) {
+	printf("%d\n", x);
+}
+
+int main() {
+
+	// 变量 t 的类型是 enum color 
+	enum  color t = yellow;
+
+	int y = blue;
+
+	printf("%d\n", y);
+
+	scanf("%d", &t);//可以当作整数输入输出
+
+	f(t);
+
+	return 0;
+}
+
+enum color {
+	red, yellow, blue, NumColors
+};
+
+int main() {
+
+	char* ColorNames[NumColors] = {
+		"red", "yellow", "blue",
+	};
+
+	char* colorName = NULL;
+	int color = 0;
+
+	printf("输入你喜欢的颜色所对应的代码：\n");
+	scanf("%d", &color);
+
+	if (color >= 0 && color < NumColors)
+		colorName = ColorNames[color];
+	else
+		colorName = "Unknowe";
+
+	printf("%s\n", colorName);
+
+	return 0;
+}
+
+enum COLOR { RED = 1, YELLOW, GREEN = 5, NumColors, };
+
+int main(void) {
+
+	printf("%d\n%d", YELLOW, NumColors);
+
+	return 0;
+}
+
+enum color {
+	red = 1, greem, yellow
+};
+
+int main(void) {
+
+	enum color t = 0;
+
+	printf("%d\n", t);
+
+	return 0;
+}
+
+struct date {
+	int year;
+	int month;
+	int day;
+};
+
+int main(void) {
+
+	struct date today;
+
+	today.year = 2020;
+	today.month = 2;
+	today.day = 9;
+
+	printf("%d年 - %d月 - %d日\n", today.year, today.month, today.day);
+
+	return 0;
+}
+
+struct point {
+	int x;
+	int y;
+};
+
+struct point p1, p2;
+
+struct {
+	int x;
+	int y;
+}; p1
+
+struct date {
+	int year;
+	int month;
+	int day;
+};
+
+int main(void) {
+
+	struct date today = { 2020, 2, 9 };
+	struct date tomorrow = { .month = 2, .day = 9 };
+
+	printf("%d - %d - %d\n", today.year, today.month, today.day);
+	printf("%d - %d - %d\n", tomorrow.year, tomorrow.month, tomorrow.day);
+
+	return 0;
+}
+
+struct date {
+	int year;
+	int month;
+	int day;
+}p1, p2;
+
+int main(void) {
+
+	//struct date p1;
+	p1 = (struct date){ 2020, 2, 9 };
+	p2 = (struct date){ 1010, 1, 5 };
+
+	p2 = p1;
+
+	printf("%d - %d - %d\n", p2.year, p2.month, p2.day);
+
+	return 0;
+}
+int main(void) {
+
+	printf("%d\n", sizeof(char*));
+	printf("%d\n", sizeof(short));
+	printf("%d\n", sizeof(long));
+	return 0;
+}
+
+#include<stdbool.h>
+
+struct date {
+	int month;
+	int day;
+	int year;
+	//月 - 日 - 年 咱得国际化！
+};
+
+bool isleap(struct date d);//判断是否为闰年
+int NumberOfDays(struct date d);//判断天数
+bool ErrorInputCheck(struct date d);//检查是否是合法输入
+
+int main(void) {
+
+	struct date today, tomorrow;
+	int flag = 0;
+
+	printf("Input today's date:(format: month day year)\n");
+	scanf("%d %d %d", &today.month, &today.day, &today.year);
+
+	if (ErrorInputCheck(today))
+		return 0;
+
+	if (today.day != NumberOfDays(today)) {
+
+		tomorrow = today;
+		tomorrow.day++;
+
+	}
+	else if (today.month != 12) {
+
+		tomorrow.day = 1;
+		tomorrow.month = today.month + 1;
+		tomorrow.year = today.year;
+
+	}
+	else {
+
+		tomorrow.day = 1;
+		tomorrow.month = 1;
+		tomorrow.year = today.year + 1;
+
+	}
+
+	printf("%d - %d - %d\n", tomorrow.month, tomorrow.day, tomorrow.year);
+
+	return 0;
+}
+
+bool ErrorInputCheck(struct date d) {
+
+	bool flag = false;
+
+	if (d.day <= 0 || d.day > 31) {
+
+		printf("illegal input of day!\n");
+		flag = true;
+
+	}
+	if (d.month <= 0 || d.month > 12) {
+
+		printf("illegal input of month!\n");
+		flag = true;
+
+	}
+	if (d.year < 0) {
+
+		printf("illegal year!\n");
+		flag = true;
+
+	}
+
+	return flag;
+}
+
+int NumberOfDays(struct date d) {
+
+	int day = 0;
+	int days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+	if (d.month == 2 && isleap)
+		day = 29;
+	else
+		day = days[d.month - 1];
+
+	return day;
+}
+
+bool isleap(struct date d) {
+
+	bool leap = false;
+	int year = d.year;
+
+	if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
+		leap = true;
+
+	return leap;
+}
+
+struct date {
+	int month;
+	int day;
+	int year;
+}myday;
+
+int main(void) {
+
+	struct date* p = &myday;
+
+	//两种访问指针结构体变量成员方式
+	(*p).month = 12;
+
+	p->month = 12;
+
+	return 0;
+}
+
+struct point {
+	int month;
+	int day;
+	int year;
+};
+
+struct point* getStruct(struct point* p);//输入结构体函数
+
+void outputStruct(struct point p);//输出结构体函数
+
+void printStruct(const struct point* p);//输出结构体函数
+
+int main(void) {
+
+	struct point y = { 0, 0, 0 };
+
+	*getStruct(&y);
+	//	*getStruct(&y) = (struct point){ 0, 0, 0 };
+
+	outputStruct(y);
+	outputStruct(*getStruct(&y));
+
+	printStruct(&y);
+
+	return 0;
+}
+
+struct point* getStruct(struct point* p) {
+
+	printf("Input a date\n");
+	scanf("%d", &p->month);
+	scanf("%d", &p->day);
+	scanf("%d", &p->year);
+
+	return p;
+}
+
+void outputStruct(struct point p) {
+
+	printf("outputStruct：\n");
+	printf("%d - %d - %d\n", p.month, p.day, p.year);
+}
+
+void printStruct(const struct point* p) {
+
+	printf("printStruct:\n");
+	printf("%d - %d - %d\n", p->month, p->day, p->year);
+}
+
+struct date {
+	int month;
+	int day;
+	int year;
+};
+
+struct date dates[100];
+struct date datess[2] = { {2, 9, 2020}, {2, 10, 2020} };
+
+struct time {
+	int hour;
+	int minute;
+	int second;
+};
+
+struct time* timeUpdate(struct time* p) {
+
+	if (p->second != 59) {
+		p->second++;
+	}
+	else if (p->minute != 59) {
+		p->second = 0;
+		p->minute++;
+	}
+	else if (p->hour != 23) {
+		p->second = 0;
+		p->minute = 0;
+		p->hour++;
+	}
+	else {
+		p->second = 0;
+		p->minute = 0;
+		p->hour = 0;
+	}
+	return p;
+}
+
+int main(void) {
+
+	struct time testTimes[5] = {
+		{11, 59, 59}, {12, 0, 0}, {1, 29, 59}, {23, 59, 59}, {19, 12, 27}
+	};
+	int i = 0;
+
+	for (i = 0; i < 5; i++) {
+
+		printf("Now the time is:%d - %d - %d\n",
+			testTimes[i].hour, testTimes[i].minute, testTimes[i].second);
+
+		testTimes[i] = *timeUpdate(&testTimes[i]);
+
+		printf("one second letter:%d - %d - %d\n",
+			testTimes[i].hour, testTimes[i].minute, testTimes[i].second);
+	}
+
+	return 0;
+}
+
+//这个结构体表示 二维坐标系中点的坐标
+struct point {
+	int x;
+	int y;
+};
+
+//这个结构体表示一个矩形 (两点确定一个矩形)
+struct rectangle {
+	struct point p1;
+	struct point p2;
+};
+
+int main(void) {
+
+	struct rectangle r;
+	r.p1.x;
+	r.p2.y;
+
+	return 0;
+}
+
+struct point {
+	int x;
+	int y;
+};
+
+struct rectangle {
+	struct point p1;
+	struct point p2;
+	struct point* p3;
+};
+
+int main(void) {
+
+	struct rectangle r, * pr;
+
+	r.p1.x;
+	(r.p1).x;
+
+	pr->p1.x;
+	(pr->p1).x;
+	//为什么访问 point 不需要用 -> 呢？
+	//因为在 rectangle 中 point 并不是指针结构体
+
+	pr->p3->x;
+
+	return 0;
+}
+
+struct point {
+	int x;
+	int y;
+};
+
+struct rectangle {
+	struct point p1;
+	struct point p2;
+
+};
+
+void printStruct(struct rectangle* p, int len) {
+
+	int i = 0;
+
+	for (i = 0; i < len; i++) {
+
+		printf("(%d, %d) (%d, %d)\n", p[i].p1.x, p[i].p1.y, p[i].p2.x, p[i].p2.y);
+	}
+}
+
+int main(void) {
+
+	struct rectangle rects[] = {
+		{{2, 2}, {4, 4} },
+		{{5, 6}, {7, 8} }
+	};
+	int len = sizeof(rects) / sizeof(rects[0]);
+
+	printStruct(rects, len);
+
+	return 0;
+}
+
+struct {
+	int x, y;
+} s[2] = {
+	{1, 3},
+	{2, 7}
+};
+
+printf("%d\n", s[0].y / s[1].x);
+
+struct sk {
+	int a;
+	float b;
+}data, * p = &data;
+
+A:	(*p).data.a;
+B:	(*p).a;
+C:	p->data.a;
+D:	p.data.a;
+
+struct { int x; int y; }x;
+struct { int x; int y; }y;
+
+A: √
+B : ×
+
+typedef long int64_t;
+
+typedef struct Adate {
+	int month;
+	int day;
+	int year;
+}date;
+
+int main(void) {
+
+	int64_t i = (int64_t)1e+10;
+	date d = { 2, 10, 2020 };
+
+	return 0;
+}
+
+typedef struct {
+	int month;
+	int day;
+	int year;
+}Date;
+
+union AnEit {
+	int i;
+	char c;
+}elt1, elt2;
+
+int main(void) {
+
+	elt1.i = 4;
+	elt2.c = 'a';
+	elt2.i = 0xDEADBEEF;
+
+	return 0;
+}
+
+typedef union {
+	int i;
+	char ch[sizeof(int)];
+}CHI;
+
+int main(void) {
+
+	CHI chi;
+	int i;
+	chi.i = 1234;
+	for (i = 0; i < sizeof(int); i++) {
+		printf("%02hhx", chi.ch[i]);
+	}
+	printf("\n");
+
+	return 0;
+}
+
+