字符串的顺序存储和操作

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

// 4.1字符串是元素类型为字符型的特殊线性表，因此也有顺序存储和链式存储
#define MAX_SIZE 100
typedef struct
{
    char str[MAX_SIZE];
    int length;
}seqString;

// 1.顺序表的初始化/置空表
void init(seqString *str)
{
    str->length = 0;
}

// 2.打印顺序表各结点的值
void display(seqString slt)
{
    if(!slt.length)
    {
        printf("顺序表是空的！\n");
        return;
    }
    for (int i = 0; i < slt.length; i++)
        printf("%c ",slt.str[i]);
    printf("\n");
}

// 3.在顺序表尾部追加值为x的元素
void append(seqString *str,char x)
{
    if(str->length == MAX_SIZE)
    {
        printf("顺序表是满的，无法追加！\n");
        exit(1);
    }
    str->str[str->length] = x;
    str->length++;
}

// 3.将字符t插到s中的第i个字符开始的位置上
void strInsert(seqString *s, int i, seqString *t)
{
    if(i < 1 || i > s->length+1)
    {
        printf("插入的位置非法！");
        return;
    }
    if(t->length+s->length > MAX_SIZE-1)
    {
        printf("字符串过长！");
        return;
    }
    for (int j = s->length-1;j >= i-1; j--)
        s->str[j+t->length] = s->str[j];
    for (int m=0; m < t->length; m++,i++)
        s->str[i-1] = t->str[m];
    s->length += t->length;
    t->length = 0;
}

// 4.将串s从第i个字符起删除len个长度的字串
void del(seqString *s, int i, int len)
{
    if(len < 1 || len > s->length-i+1)
    {
        printf("操作非法，无法删除！\n");
        return;
    }
    for (; i < s->length; i++)
    {
        s->str[i-1] = s->str[i+len-1];
    }
    s->length -= len;
}

// 5.字符串拼接
void strConcat(seqString *s, seqString *t)
{
    if(s->length + t->length > MAX_SIZE)
    {
        printf("空间不足，无法拼接！\n");
        return;
    }
    for (int i = 0; i < t->length; i++)
    {
        s->str[s->length++] = t->str[i];
    }
}

// 6. 求字串
seqString *substring(seqString s, int i, int len)
{
    seqString *p = (seqString*) malloc(sizeof(seqString));
    init(p);
    if(len < 1 || len > s.length-i+1)
    {
        printf("获取字串操作非法!\n");
        return p;
    }
    for (int j = 0; j < len; i++)
        p->str[j++] = s.str[i-1];
    p->length = len;
    return p;
}

int main()
{
    seqString s,t;
    init(&s);
    init(&t);
    for (int i = 'a'; i < 'f'; ++i)
        append(&s,(char)i);
    printf("字符串s: ");
    display(s);
    for (int i = 'A'; i < 'D'; ++i)
        append(&t,(char)i);
    printf("字符串t: ");
    display(t);
    printf("把字符串t拼接在s后\n");
    strConcat(&s,&t);
    printf("字符串s: ");
    display(s);
    int i = 3;
    printf("将字符t插到s中的第%d个字符开始的位置上\n",i);
    strInsert(&s,i,&t);
    printf("字符串s: ");
    display(s);
    int len = 3;
    printf("将串s从第%d个字符起删除%d个长度的字串\n",i,len);
    del(&s,i,len);
    printf("字符串s: ");
    display(s);
    seqString *str = substring(s,i,len);
    printf("字符串s从第%d个字符开始长度为%d的字串:\n",i,len);
    display(*str);
    return 0;
}