5-16

2026-11-02 22:23:48 +08:00 · 2020-05-16 19:48:41 +08:00
parent 5c19c7c0f1
commit 1a5ae06541
147 changed files with 811 additions and 3837 deletions
--- a/Examples/常见字符串函数/Test/main.c
+++ b/Examples/常见字符串函数/Test/main.c
@@ -0,0 +1,285 @@
+#define _CRT_SECURE_NO_WARNINGS 1
+
+#include<stdio.h>
+#include<string.h>
+
+int main(void) {
+
+	char ch = -1;
+
+	int a = 0;
+
+	a = putchar(ch);
+
+	printf("\n%d", a);
+
+	return 0;
+
+}
+
+int main(void) {
+
+	int ch;
+
+	while ((ch = getchar()) != EOF) {
+		putchar(ch);
+	}
+
+	printf("EOF\n");
+
+	return 0;
+}
+
+int main() {
+
+	char str[] = { 'H', 'E', 'L', 'L', 'O', };
+
+	printf("%d\n", strlen(str));
+
+	printf("%d\n", strnlen_s(str, (size_t)sizeof(str)));
+
+	return 0;
+}
+
+int test(const char* str) {
+
+	str++;
+	*str = '1';
+}
+
+int main() {
+
+	char str[] = { 'H', 'I', '!' };
+
+	str++;
+
+	printf("%d\n", test(str));
+
+	return 0;
+}
+
+int mystrlen(const char* str) {
+
+	char* end = str;
+
+	while (*end++);
+
+	//退出while循环时，多加了一次 1
+	return end - str - 1;
+
+}
+
+int main() {
+
+	char* str = "Hello World!";
+
+	printf("%d\n", mystrlen(str));
+
+	return 0;
+}
+
+int mystrcmp(char* str1, char* str2) {
+
+	int ret = 0;
+
+	while ((ret = ((unsigned char)*str1 - (unsigned char)*str2)) == 0 && *str1) {
+		++str1, ++str2;
+	}
+
+	return ret;
+}
+
+UINT_MAX
+
+int main() {
+
+	char* str1 = "abc ";
+	char* str2 = "abc";
+
+	printf("%d\n", mystrcmp(str1, str2));
+
+	return 0;
+}
+
+int main() {
+
+	char* str1 = NULL;
+	char* str2 = "Hello";
+
+	printf("%d\n", strcmp(str1, str2));
+	printf("%d\n", strncmp(str1, str2, 1));
+
+	return 0;
+}
+
+int mystrcmp(char* str1, char* str2) {
+
+	while (*str1 == *str2 && *str1)
+		++str1, ++str2;
+
+	return (*str1 - *str2);
+}
+
+int main() {
+
+	char* str1 = "Hello ";
+	char* str2 = "Hello";
+
+	printf("%d\n", mystrcmp(str1, str2));
+
+	return 0;
+}
+
+int main() {
+
+	char* str1 = "Hello";
+	char* str2 = "Hello";
+
+	//strcpy(str1, str2);
+	strncpy(str1, str2, 5);
+
+	puts(str1);
+
+	return 0;
+}
+
+int main() {
+
+	char str1[] = "Hello";
+	char str2[] = "Hello";
+
+	//strcpy(str1, str2);
+	strncpy(str1, str2, 6);
+
+	puts(str1);
+
+	return 0;
+}
+
+int main() {
+
+	char str1[] = "hello";
+	char str2[] = "hello world";
+
+	strcpy(str1, str2);
+	//strncpy(str1, str2, 5);
+
+	puts(str1);
+
+	return 0;
+}
+
+
+int main() {
+
+	char* str1 = "Hello";
+	char* str2 = "Hello World";
+
+	strcpy(str1, str2);
+	strncpy(str1, str2, 12);
+
+	puts(str1);
+
+	return 0;
+}
+int main() {
+
+	char str1[] = "Hello World";
+	char str2[] = { 'H', 'e', 'l','l', 'o' };
+
+	strncpy(str1, str2, 10);
+
+	puts(str1);
+
+	return 0;
+}
+
+int main() {
+
+	char str1[] = "Hello World";
+	char str2[] = "World";
+
+	//strncpy(str1, str2, 10);
+	strcpy(str1, str2);
+	puts(str1);
+
+	return 0;
+}
+
+#include<assert.h>
+
+char* mystrcpy(char* str1, char* str2) {
+
+	assert(str1 != NULL && str2 != NULL);
+	assert(strlen(str1) >= strlen(str2));
+
+	//核心代码从这里开始， 上面的不懂可以加QQ群问我（群在我公众号关注回复的消息里）
+	char* after = str1;
+
+	while (*str1++ = *str2++);
+
+	return after;
+}
+
+int main() {
+
+	char* str1 = "HI!!!";
+	char* str2 = "Hello";
+
+	mystrcpy(str1, str2);
+	puts(str1);
+
+	return 0;
+}
+
+int main() {
+
+	char str1[11] = "Hello";
+	char str2[3] = { 'J', 'I', 'M' };
+
+	strcat(str1, str2);
+	puts(str1);
+
+	return 0;
+}
+
+int main() {
+
+	char str2[3] = { 'J', 'I', 'M' };
+	char str1[3] = "JIM";
+
+
+	printf("%d\n", strcmp(str1, str2));
+
+
+	return 0;
+}
+
+int main() {
+
+	char str1[8] = "hi";
+	char str2[4] = "you";
+
+	strncat(str1, str2, 5);
+	puts(str1);
+
+	return 0;
+}
+
+char* mystrcat(char* str1, char* str2) {
+
+	while (str1[strlen(str1)] = *str2++);
+
+	return str1;
+}
+
+int main() {
+
+	char str1[8] = "Hi";
+	char str2[4] = "YOU";
+
+	mystrcat(str1, str2);
+	puts(str1);
+
+	return 0;
+}
--- a/Examples/常见字符串函数/Test/readme.md
+++ b/Examples/常见字符串函数/Test/readme.md
@@ -0,0 +1 @@
+ 写文章中的测试代码
--- a/Examples/常见字符串函数/mystrcmp/VSstrcmp.c
+++ b/Examples/常见字符串函数/mystrcmp/VSstrcmp.c
@@ -0,0 +1,29 @@
+//这是我能理解的格式
+int mystrcmp(char* str1, char* str2) {
+
+	int ret = 0;
+
+	while ((ret = ((unsigned char)*str1 - (unsigned char)*str2)) == 0 && *str1) {
+		++str1, ++str2;
+	}
+
+	return ret;
+}
+
+
+//原版在这里
+int __cdecl strcmp(
+	const char* src,
+	const char* dst
+)
+{
+	int ret = 0;
+
+	while ((ret = *(unsigned char*)src - *(unsigned char*)dst) == 0 && *dst)
+	{
+		++src, ++dst;
+	}
+	
+	//这里不太理解，那个大神理解了可以给我讲一下，谢谢
+	return ((-ret) < 0) - (ret < 0); // (if positive) - (if negative) generates branchless code
+}
--- a/Examples/常见字符串函数/mystrcmp/main.c
+++ b/Examples/常见字符串函数/mystrcmp/main.c
@@ -0,0 +1,11 @@
+
+
+int main() {
+
+	char* str1 = "Hello ";
+	char* str2 = "Hello";
+
+	printf("%d\n", mystrcmp(str1, str2));
+
+	return 0;
+}
--- a/Examples/常见字符串函数/mystrcmp/mystrcmp.c
+++ b/Examples/常见字符串函数/mystrcmp/mystrcmp.c
@@ -0,0 +1,7 @@
+int mystrcmp(char* str1, char* str2) {
+
+	while (*str1 == *str2 && *str1)
+		++str1, ++str2;
+
+	return (*str1 - *str2);
+}
--- a/Examples/结构/stucture-as-func-parameter/main.c
+++ b/Examples/结构/stucture-as-func-parameter/main.c
@@ -0,0 +1,99 @@
+#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;
+}
--- a/Examples/结构/stucture-as-func-parameter/readme.md
+++ b/Examples/结构/stucture-as-func-parameter/readme.md
@@ -0,0 +1,22 @@
+## 结构体作为函数参数
+**明天的日期**
+*写一个程序:输入今天的日期,求明天的日期*
+
+看着这个问题简单,实际上稍微有点技巧.
+
+给出下面四个特殊日期,大家可以思考一下:
+
+>2020 - 1 -31
+>
+>2020 - 11 - 31
+>
+>2020 - 12 - 31
+>
+>2000 - 2 - 28
+
+## Use sturcture itself as a function's parameter
+it's not an efficient way
+
+>K & R said （p.131 ）
+>"if a large structure is to be passed to a function,
+>in is generally more efficent to pass a pointer than to copy the whole structure"
--- a/Examples/结构/test/test.c
+++ b/Examples/结构/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;
+}
+
+
--- a/Examples/编写大型程序/test.c
+++ b/Examples/编写大型程序/test.c
@@ -0,0 +1,234 @@
+#define _CRT_SECURE_NO_WARNINGS 1
+
+#include<stdio.h>
+
+//全局变量
+
+int f(void);
+
+int gAll = 12;
+
+int main(void){
+	
+	//__func__ 可以打印出当前函数的函数名，下划线一边是两个
+	printf("in %s gAll = %d\n", __func__, gAll);
+	f();
+	printf("again in %s gAll = %d\n", __func__, gAll);
+
+	return 0;
+}
+
+int f(void) {
+	
+	printf("in %s gAll = %d\n", __func__, gAll);
+	gAll += 2;
+	printf("again in %s gAll = %d\n", __func__, gAll);
+
+	return gAll;
+}
+
+int gAll = 12;
+int g = gAll;
+
+int main(void) {
+
+	return 0;
+}
+
+const int gAll = 12;
+int g = gAll;
+
+int main(void) {
+
+	return 0;
+}
+
+int f(void);
+
+int gAll = 12;
+
+int main(void) {
+	
+	int gAll = 2;
+
+	printf("in %s gAll = %d\n", __func__, gAll);
+
+	f();
+
+	printf("again in %s gAll = %d\n", __func__, gAll);
+
+	return 0;
+}
+
+int f(void) {
+	
+	printf("in %s gAll = %d\n", __func__, gAll);
+	gAll += 2;
+	printf("again in %s gAll = %d\n", __func__, gAll);
+
+	return gAll;
+}
+
+int f(void);
+
+int main(void) {
+
+	f();
+	f();
+	f();
+
+	return 0;
+}
+
+int f(void) {
+
+	static int All = 1;
+	printf("in %s All = %d\n", __func__, All);
+	All += 2;
+	printf("again in %s All = %d\n", __func__, All);
+
+	return All;
+}
+
+int f(void);
+
+int gAll = 12;
+
+int main(void) {
+
+	printf("1 st\n");
+	f();
+	printf("2 nd\n");
+	f();
+
+	return 0;
+}
+
+int f(void) {
+	
+	int a = 0;
+	int b = 0;
+	static int All = 1;
+
+	printf("&All :  %p\n", &All);
+	printf("&gAll:  %p\n", &gAll);
+	printf("&a :    %p\n", &a);
+	printf("&b :    %p\n", &b);
+
+	return All;
+}
+
+int* f(void);
+void g(void);
+
+int main(void) {
+
+	int* p = f();
+	printf("*p = %d\n", *p);
+	g();
+	printf("*p = %d\n", *p);
+
+	return 0;
+}
+
+int* f(void) {
+
+	int i = 12;
+
+	return &i;
+}
+void g(void) {
+
+	int k = 24;
+	
+	printf("k = %d\n", k);
+
+	return k;
+}
+
+编译预处理 与 宏
+
+#include<stdio.h>
+
+const double PI = 3.14159;
+
+int main(void) {
+
+	printf("%f\n", 2 * PI * 3.0);
+	return 0;
+}
+
+#include<stdio.h>
+
+#define PI  3.14159
+//注意：不写分号 不写等于号
+
+int main(void) {
+
+	printf("%f\n", 2 * PI * 3.0);
+	return 0;
+}
+
+int main(void) {
+
+	printf("%s : %d\n", __FILE__, __LINE__);
+	printf("%s %s\n", __DATE__, __TIME__);
+
+	return 0;
+}
+
+#define cube(x) ((x) * (x) * (x))
+
+int main(void) {
+
+	printf("%d\n", cube(5));
+	return 0;
+}
+
+#define ERROR1(x) (x * 57)
+#define ERROR2(x) (x) * 57
+
+int main(void) {
+	
+	int i = 1;
+	printf("%d\n", ERROR1(i + 2));
+	printf("%d\n", 300 / ERROR2(1));
+
+	return 0;
+}
+
+#define PRETTY_PRINT(msg) printf(msg);
+
+int main(void) {
+
+	int n = 0;
+
+	printf("Input an number\n");
+	scanf("%d", &n);
+
+	if (n < 10)
+		PRETTY_PRINT("less than 10\n");
+	else
+		PRETTY_PRINT("more than 10\n");
+
+	return 0;
+}
+
+#include<stdio.h>
+#include<string.h>
+
+#define TOUPPER(c) ('a' <= (c) && (c) <= 'z' ? (c) - 'a' + 'A' : (c))
+
+int main(void) {
+
+	int i = 0;
+	char s[1000];
+	strcpy(s, "abcd");
+	putchar(TOUPPER(s[++i]));
+
+	return 0;
+}
+
+大程序结构
+
+
--- a/Examples/输入&输出/binary
+++ b/Examples/输入&输出/binary
@@ -0,0 +1,45 @@
+#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);
+	}
+}
--- a/Examples/输入&输出/binary
+++ b/Examples/输入&输出/binary
@@ -0,0 +1,4 @@
+程序中向文件中写入/读取2进制文本
+
+linux 下可以用 `od` 命令打开文件
+
--- a/Examples/输入&输出/binary
+++ b/Examples/输入&输出/binary
@@ -0,0 +1,11 @@
+#ifndef _STUDENT_H_
+#define _STUDENT_H_
+
+#define STR_LEN  20
+
+typedef struct _student {
+	char name[STR_LEN];
+	char gender;
+	char age;
+}Student;
+#endif
--- a/Examples/输入&输出/binary
+++ b/Examples/输入&输出/binary
@@ -0,0 +1,66 @@
+#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", "wx");//如果要向student.data反复写入数据，将 wx 改为 x
+	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
+}
--- a/Examples/输入&输出/test
+++ b/Examples/输入&输出/test
@@ -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);
+	}
+}