C语言使用堆分配存储表示字符串

C语言使用堆分配存储表示字符串

串S = ‘aafhjkxdeeshtksslshtvdfdhshtksslshtbfdmhgshtksslshtsfesrgb’
用堆分配存储表示字符串S，然后先在pos=5的位置插入‘xdfykytyg’，再在pos=10的位置删除长度为7的子串。

代码：

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

typedef struct
{
    char *ch;
    int length;
} sstring;

//chars为字符串常量，生成一个其值等于chars的串
void StrAssign(sstring *t, char *chars)
{
    int i;
    char *c;
    for (i = 0, c = chars; c[i] != '\0'; i++)
        if (!i)
        {
            t->ch = NULL;
            t->length = 0;
        }
        else
        {
            t->ch = (char *)malloc((i + 1) * sizeof(char));
            for (int j = 0; j <= i; j++)
            {
                t->ch[j] = chars[j];
            }
            t->length = i + 1;
        }
}

//销毁串
void DestroyString(sstring *s)
{
    free(s->ch);
    s->ch = NULL;
    s->length = 0;
}

//打印输出串
void print(sstring T)
{
    int i;
    for (i = 0; i < T.length; i++)
    {
        printf("%c", T.ch[i]);
    }
    printf("\n");
}

//在串的第pos个字符之前插入串T
void StrInsert(sstring *s, int pos, sstring T)
{
    int i;
    if (T.length != 0)
    {
        s->ch = (char *)realloc(s->ch, (s->length + T.length) * sizeof(char));
        for (i = s->length - 1; i >= pos - 1; --i)
        {
            s->ch[i + T.length] = s->ch[i];
        }
        for (i = 0; i <= T.length - 1; i++)
        {
            s->ch[pos - 1 + i] = T.ch[i];
        }
        s->length += T.length;
    }
}

void StrDelete(sstring *s, int pos, int len)
{
    int i;
    for (i = pos + len - 1; i < s->length; i++)
    {
        s->ch[i - len] = s->ch[i];
    }
    s->length -= len;
}

void main()
{
    sstring S1, S2;
    S1.ch = NULL;
    S2.ch = NULL;

    StrAssign(&S1, "aafhjkxdeeshtksslshtvdfdhshtksslshtbfdmhgshtksslshtsfesrgb");
    StrAssign(&S2, "xdfykytyg");

    StrInsert(&S1, 5, S2);
    printf("insert success ! \nS=");
    print(S1);

    StrDelete(&S1, 10, 7);
    printf("delete success ! \nS=");
    print(S1);

    DestroyString(&S1);
    DestroyString(&S2);
}