From a2ebbae000aab697bda7c6f4a67374e35c7caa99 Mon Sep 17 00:00:00 2001
From: ViolentAyang <76544389+ViolentAyang@users.noreply.github.com>
Date: Fri, 1 Apr 2022 16:36:39 +0800
Subject: [PATCH] =?UTF-8?q?Create=20=E5=AD=97=E7=AC=A6=E4=B8=B2=E5=9F=BA?=
 =?UTF-8?q?=E6=9C=AC=E6=93=8D=E4=BD=9C.c?=
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---
 字符串基本操作.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 字符串基本操作.c

diff --git a/字符串基本操作.c b/字符串基本操作.c
new file mode 100644
index 0000000..853fe29
--- /dev/null
+++ b/字符串基本操作.c
@@ -0,0 +1,79 @@
+#include<stdio.h>
+#include<stdlib.h>
+#include<stdbool.h>
+#define MAXLEN 255
+
+typedef struct{
+	char ch[MAXLEN];
+	int length;
+}SString;
+
+//求子串 用Sub返回串S的第pos个字符起长度为len的子串
+bool SubString(SString *Sub,SString S,int pos,int len){
+	if(pos+len-1>S.length){
+		return false;
+	}
+	for(int i=pos;i<pos+len;i++){
+		Sub->ch[i-pos+1] = S.ch[i];
+	}
+	Sub->length = len;
+	return true;
+}
+//比较操作 若S>T,则返回值>0；若S=T，则返回值=0；若S<T，则返回值<0
+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];
+		}
+	}
+	//扫描到所有字符都相同，则长度长的串更大
+	return S.length - T.length;
+}
+//定位操作 若主串S中存在与串T值相同的子串，则返回它在主串S中第一次出现的位置，否则函数值为0
+int Index(SString S,SString T){
+	int i = 1,n = S.length,m = T.length;
+	SString Sub; //用于暂存子串
+	while(i<=n-m+1){
+		SubString(&Sub,S,i,m);
+		if(StrCompare(Sub,T)!=0){
+			++i;
+		}else{
+			return i; //返回子串在主串中的位置
+		}
+	}
+	return 0; //S中不存在与T相等的子串
+}
+//字符串赋值操作
+void assign(SString *S){
+	printf("请输入字符串：\n");	
+	char x;
+	int i = 1;
+	scanf("%c",&x);
+	while(x!='\n'){
+		S->ch[i] = x;
+		i ++;
+		scanf("%c",&x);
+	}
+	S->length = i-1;
+}
+//打印字符串
+void printString(SString S){
+	for(int i=1;i<=S.length;i++){
+		printf("%c",S.ch[i]);
+	}
+	printf("\n");
+}
+int main(){
+	SString S,T;
+	assign(&S);
+	assign(&T);
+	printf("求子串操作：\n");
+	SString Sub;
+	SubString(&Sub,S,2,3);
+	printString(Sub);
+	printf("比较操作：\n");
+	printf("S串和T串是否相等：%d\n",StrCompare(S,T));
+	printf("定位操作：\n");
+	printf("出现位置:%d",Index(S,T));
+	return 0;
+}