假设以单链表结构表示串每个结点数据域存放一个字符且附设头结点。试用c语言编写算法实现串的下列基本操作StrAsignSchars;StrCopyST;StrCompareST;StrLengthS;StrCatST;SubStringSubSposlen

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

#define MAXSIZE 100

typedef struct Node {
    char data;
    struct Node *next;
} Node, *LinkedList;

void StrAssign(LinkedList S, char *chars) {
    int i = 0;
    Node *p = S;
    while (chars[i] != '\0') {
        Node *newNode = (Node*) malloc(sizeof(Node));
        newNode->data = chars[i++];
        newNode->next = NULL;
        p->next = newNode;
        p = newNode;
    }
}

void StrCopy(LinkedList S, LinkedList T) {
    Node *p = S->next;
    Node *q = T->next;
    while (p != NULL) {
        Node *newNode = (Node*) malloc(sizeof(Node));
        newNode->data = p->data;
        newNode->next = NULL;
        q->next = newNode;
        q = newNode;
        p = p->next;
    }
}

int StrCompare(LinkedList S, LinkedList T) {
    Node *p = S->next;
    Node *q = T->next;
    while (p != NULL && q != NULL) {
        if (p->data != q->data) {
            return p->data - q->data;
        }
        p = p->next;
        q = q->next;
    }
    return p == NULL ? -1 : 1;
}

int StrLength(LinkedList S) {
    int len = 0;
    Node *p = S->next;
    while (p != NULL) {
        len++;
        p = p->next;
    }
    return len;
}

void StrCat(LinkedList S, LinkedList T) {
    Node *p = S;
    while (p->next != NULL) {
        p = p->next;
    }
    Node *q = T->next;
    while (q != NULL) {
        Node *newNode = (Node*) malloc(sizeof(Node));
        newNode->data = q->data;
        newNode->next = NULL;
        p->next = newNode;
        p = newNode;
        q = q->next;
    }
}

void SubString(LinkedList Sub, LinkedList S, int pos, int len) {
    int i = 1;
    Node *p = S->next;
    while (p != NULL && i < pos) {
        p = p->next;
        i++;
    }
    Node *q = Sub;
    while (p != NULL && i <= pos + len - 1) {
        Node *newNode = (Node*) malloc(sizeof(Node));
        newNode->data = p->data;
        newNode->next = NULL;
        q->next = newNode;
        q = newNode;
        p = p->next;
        i++;
    }
}

int main() {
    LinkedList S = (LinkedList) malloc(sizeof(Node));
    S->next = NULL;
    StrAssign(S, "hello");
    printf("S: ");
    Node *p = S->next;
    while (p != NULL) {
        printf("%c", p->data);
        p = p->next;
    }
    printf("\n");

    LinkedList T = (LinkedList) malloc(sizeof(Node));
    T->next = NULL;
    StrCopy(S, T);
    printf("T: ");
    p = T->next;
    while (p != NULL) {
        printf("%c", p->data);
        p = p->next;
    }
    printf("\n");

    printf("S compare T: %d\n", StrCompare(S, T));

    printf("S length: %d\n", StrLength(S));

    StrCat(S, T);
    printf("S cat T: ");
    p = S->next;
    while (p != NULL) {
        printf("%c", p->data);
        p = p->next;
    }
    printf("\n");

    LinkedList Sub = (LinkedList) malloc(sizeof(Node));
    Sub->next = NULL;
    SubString(Sub, S, 2, 4);
    printf("Sub: ");
    p = Sub->next;
    while (p != NULL) {
        printf("%c", p->data);
        p = p->next;
    }
    printf("\n");

    return 0;
}
``