串——串的链式存储结构设计思路与实现

总的实现代码：

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

// 定义链式存储的字符节点
typedef struct CharNode {
    char data;                  // 存储字符
    struct CharNode* next;      // 指向下一个节点
} CharNode;

// 定义字符串结构
typedef struct {
    CharNode* head;     // 指向链表的头节点
    int length;         // 字符串长度
} String;

// 初始化字符串
void InitStr(String* str) 
{
    str->head = NULL;
    str->length = 0;
}

// 释放字符串内存
void StrFree(String* str) 
{
    CharNode* current = str->head;
    CharNode* nextNode;
    while (current != NULL) 
	{
        nextNode = current->next;
        free(current);
        current = nextNode;
    }
    str->head = NULL;
    str->length = 0;
}

// 从 C 字符串初始化链式字符串
void StrCopy(String* str, const char* cstr)
{	
    InitStr(str);
	if(*cstr == '\0')		// 判断不是空字符 
        return;
    
    CharNode *p = NULL;
    CharNode* newNode = (CharNode*)malloc(sizeof(CharNode));
    newNode->data = *cstr++;
    newNode->next = str->head;
    str->head = newNode; // 插入到链表头部
    p = newNode; 
    while (*cstr)
	{
        CharNode* Node = (CharNode*)malloc(sizeof(CharNode));
        Node->data = *cstr++;
        p->next = Node;
        Node->next = NULL;
        p = Node; // 插入到链表头部
        str->length++;
    }
}

// 计算字符串长度
int stringLength(String* str) 
{
    return str->length;
}

// 字符串拼接
void StrCat(String* dest, const String* src)
{
    CharNode* current = src->head;
    while (current != NULL)
	{
        CharNode* newNode = (CharNode*)malloc(sizeof(CharNode));
        newNode->data = current->data;
        newNode->next = NULL;

        // 将新节点添加到目标字符串的尾部
        if (dest->head == NULL) 
		{
            dest->head = newNode; // 如果目标字符串为空
        }
		else
		{
            CharNode* tail = dest->head;
            while (tail->next != NULL)
			{
                tail = tail->next; // 找到尾部
            }
            tail->next = newNode; // 添加新节点
        }
        dest->length++;
        current = current->next;
    }
}

// 查找子字符串
int StrFind(const String* str, const char* substring)
{
    CharNode* current = str->head;
    CharNode* subCurrent;
    int index = 0;

    while (current != NULL) 
	{
        subCurrent = current;
        int subIndex = 0;

        // 检查是否匹配子字符串
        while (subCurrent != NULL && substring[subIndex] != '\0' && subCurrent->data == substring[subIndex])
		{
            subCurrent = subCurrent->next;
            subIndex++;
        }

        // 如果匹配到子字符串的末尾
        if (substring[subIndex] == '\0')
		{
            return index; // 返回起始位置
        }

        current = current->next;
        index++;
    }
    return -1; // 未找到
}

// 显示字符串
void StrShow(const String* str)
{
    CharNode* current = str->head;
    while (current != NULL)
	{
        putchar(current->data);
        current = current->next;
    }
    putchar('\n');
}

// 主函数示例
int main()
{
    String str1;
    StrCopy(&str1, "Hello");
    StrCopy(&str1, "hello");
    StrShow(&str1);

    String str2;
    StrCopy(&str2, " World!");

    printf("字符串1: ");
    StrShow(&str1);
    printf("字符串2: ");
    StrShow(&str2);

    // 拼接字符串
    StrCat(&str1, &str2);
    printf("拼接后的字符串: ");
    StrShow(&str1);

    // 查找子字符串
    const char* substring = "lo";
    int position = StrFind(&str1, substring);
    if (position != -1)
	{
        printf("子字符串 \"%s\" 在位置 %d\n", substring, position);
    }
	else
	{
        printf("子字符串 \"%s\" 未找到\n", substring);
    }

    // 释放内存
    StrFree(&str1);
    StrFree(&str2);

    return 0;
}