From 0621caa47f0fadddf3ed299b576509b21ca99b0e Mon Sep 17 00:00:00 2001
From: hairrrrr <781728963@qq.com>
Date: Sun, 9 Feb 2020 00:19:14 +0800
Subject: [PATCH] 2-8

---
 .../13 String/Prelesson/code/Test/main.c      | 285 ++++++++++++++++++
 .../13 String/Prelesson/code/Test/readme.md   |   1 +
 2 files changed, 286 insertions(+)
 create mode 100644 C Crash Course/13 String/Prelesson/code/Test/main.c
 create mode 100644 C Crash Course/13 String/Prelesson/code/Test/readme.md

diff --git a/C Crash Course/13 String/Prelesson/code/Test/main.c b/C Crash Course/13 String/Prelesson/code/Test/main.c
new file mode 100644
index 0000000..9f81f26
--- /dev/null
+++ b/C Crash Course/13 String/Prelesson/code/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;
+}
diff --git a/C Crash Course/13 String/Prelesson/code/Test/readme.md b/C Crash Course/13 String/Prelesson/code/Test/readme.md
new file mode 100644
index 0000000..fe454f7
--- /dev/null
+++ b/C Crash Course/13 String/Prelesson/code/Test/readme.md	
@@ -0,0 +1 @@
+ 鍐欐枃绔犱腑鐨勬祴璇曚唬鐮�
\ No newline at end of file