一、字符串的组成

        1.数据域，字符串的内容

        2.字符串的长度

二、模式匹配-暴力匹配原理

        1.两个字符串一个主串一个模式串用两个指针对其进行匹配

         2、两个指针所对应的值相同时继续匹配下一个

        

         3、当出现不匹配的情况时，回溯主串的指针到刚开始起点的下一个位置，模式串回到最初的位置。

         4、当主串超出索引时结束匹配，判断模式串是否在最后一个位置来检查是否完成匹配。

三、暴力匹配算法代码实现

        1.初始化字符串

String* InitString(void)
{
	String* S = (String*)malloc(sizeof(String));
	S->data = NULL;
	S->length = 0;
	return S;
}

         2.向字符串中增加元素

void stringAssign(String* s, char* data)
{
	if (s->data)
	{
		free(s->data);
	}
	int len = 0;
	char* temp = data;
	while (*temp)
	{
		temp++;
		len++;
	}
	if (len == 0)
	{
		s->data = NULL;
		s->length = 0;

	}
	else {
		temp = data;
		s->length = len;
		s->data = (char*)malloc(sizeof(char) * (len + 1));
		for (int i = 0; i < len; i++,temp++)
		{
			s->data[i] = *temp;
		}
	}
}

        3.打印字符串

void PrintString(String* s)
{
	for (int i = 0; i < s->length; i++)
	{
		printf(i == 0 ? "%c" : "->%c", s->data[i]);
	}
	printf("\n");
}

        4.暴力匹配算法代码实现

void Forcemach(String* master, String* sub)
{
	int i = 0, j = 0;
	while (i < master->length && j < sub->length)
	{
		if (master->data[i] == sub->data[j])
		{
			i++; j++;
		}
		else {
			i = i - j + 1;
			j = 0;
		}
	}
	if (j == sub->length)
	{
		printf("success");
	}
	else printf("fail");
}

        5.完整工程代码

#include<stdio.h>
#include<stdlib.h>
typedef struct String
{
	char* data;
	int length;
}String;

String* InitString(void)
{
	String* S = (String*)malloc(sizeof(String));
	S->data = NULL;
	S->length = 0;
	return S;
}
void stringAssign(String* s, char* data)
{
	if (s->data)
	{
		free(s->data);
	}
	int len = 0;
	char* temp = data;
	while (*temp)
	{
		temp++;
		len++;
	}
	if (len == 0)
	{
		s->data = NULL;
		s->length = 0;

	}
	else {
		temp = data;
		s->length = len;
		s->data = (char*)malloc(sizeof(char) * (len + 1));
		for (int i = 0; i < len; i++,temp++)
		{
			s->data[i] = *temp;
		}
	}
}
void PrintString(String* s)
{
	for (int i = 0; i < s->length; i++)
	{
		printf(i == 0 ? "%c" : "->%c", s->data[i]);
	}
	printf("\n");
}
void Forcemach(String* master, String* sub)
{
	int i = 0, j = 0;
	while (i < master->length && j < sub->length)
	{
		if (master->data[i] == sub->data[j])
		{
			i++; j++;
		}
		else {
			i = i - j + 1;
			j = 0;
		}
	}
	if (j == sub->length)
	{
		printf("success");
	}
	else printf("fail");
}
int main()
{
	String* string1= InitString();
	String* string2 = InitString();
	stringAssign(string1,"Hello world!");
	stringAssign(string2, "Hello world!");
	Forcemach(string1, string2);
	return 0;
}