From 058aee570cf0ae3964d2de246a9c8643efa99fb9 Mon Sep 17 00:00:00 2001
From: applepiget <1291438813@qq.com>
Date: Wed, 6 Jul 2022 15:39:01 +0800
Subject: [PATCH] =?UTF-8?q?Create=20=E4=B8=B2=EF=BC=88String=EF=BC=89.md?=
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 ...\270\262\357\274\210String\357\274\211.md" | 118 ++++++++++++++++++
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 create mode 100644 "\344\270\262/\344\270\262\357\274\210String\357\274\211.md"

diff --git "a/\344\270\262/\344\270\262\357\274\210String\357\274\211.md" "b/\344\270\262/\344\270\262\357\274\210String\357\274\211.md"
new file mode 100644
index 0000000..6ecf3f7
--- /dev/null
+++ "b/\344\270\262/\344\270\262\357\274\210String\357\274\211.md"
@@ -0,0 +1,118 @@
+## 串（String）
+
+### 1.串的基本操作
+
+通常以字串为操作对象
+
+![](D:\笔记\数据结构\思维导图\串的基本操作.png)
+
+```c++
+#define maxlen 255
+typedef struct{
+	char ch[maxlen];
+	int length;
+}SString;
+
+
+//取出一个子串
+bool SubString(SString &Sub , SString S , int pos , int len)
+{
+    if(pos + len > S.length)
+        return false;			//防止字串越界
+    for(int i = pos ; i < pos + len ; i ++)
+        Sub.ch[i - pos + 1] = S.ch[i];
+    Sub.length = len;
+    return true;
+}
+
+
+//比较字符串
+int StrCompare(SString S , SString T)
+{
+    for(int i = 0 ; i < S.length && i < T.length ; i ++)
+        if(S.ch[i] != T.ch[i])
+            return S.ch[i] - T.ch[i];
+    
+    return S.length - T.length;
+}
+
+
+//定位操作
+int Index(SString S , SString T)
+{
+    int i = 1, n = StrLength(S) , m = StrLength(T);
+    SString sub;
+    while(i <= n - m + 1)
+    {
+        SubString(sub , S , i , m);
+        if(StrCompare(sub , T) != 0)
+            ++i;
+        else
+            return i;
+	}
+    return 0;
+}
+```
+
+
+
+字符集：
+英文字符 --- ASCII
+
+中英文 --- Unicode
+
+
+
+---
+
+
+
+### 2.串的存储结构
+
+1.顺序存储
+
+```c++
+//定长分配存储
+#define maxlen 255
+typedef struct{
+	char ch[maxlen];
+	int length;
+}SString;
+
+
+//堆分配存储
+typedef struct{
+	char *ch;
+    int length;
+}HString;
+	HString S;
+	S.ch = (char*) malloc (maxlen * sizeof(char));
+	S.length = 0;
+```
+
+
+
+2.链式存储
+
+```c++
+typedef struct{
+	char ch;
+	struct StringNode *next;
+}StringNode , *String;
+```
+
+![串的链式存储1](D:\笔记\数据结构\思维导图\串的链式存储1.png)
+
+上述方式存储密度低，优化如下:
+
+```c++
+typedef struct{
+	char ch[4];
+	struct StringNode *next;
+}StringNode , *String;
+```
+
+![串的链式存储2](D:\笔记\数据结构\思维导图\串的链式存储2.png)
+
+
+