模拟实现strcpy、strcat、strstr、strchr、strcmp、memcpy、memmove

#include<stdio.h>
#include<windows.h>
#include<assert.h>
#include <memory.h>


char *my_strcpy(char *dst, const char *src)
{
    assert(dst);
    assert(src);
    char *ret = dst;
    while (*dst++ = *src++)
    {
        ;
    }
    return ret;
}

char *my_strcat(char *dst, const char *src)
{
    assert(dst);
    assert(src);
    char *ret = dst;
    while (*dst != '\0')
    {
        dst++;
    }
    dst = dst;
    while (*dst++ = *src++)
    {
        ;
    }
    return ret;
}
int my_strlen(const char *p)
{
    assert(p);
    int count = ;
    while (*p++ != '\0')
    {
        count++;
    }
    return count;
}
char *my_strstr(const char *dst, const char *src)
{
    assert(dst);
    assert(src);
    const char *pdst = dst;
    const char*psrc = src;
    int len = my_strlen(psrc);
    while (my_strlen(dst) < my_strlen(src))
    {
        break;
    }
    while (my_strlen(pdst) > len)
    {
        while (*dst != *psrc)
        {
            dst++;
        }
        psrc = src;
        pdst = dst;
        while (*dst == *psrc)
        {
            dst++,psrc++;
        }
        if (*psrc == '\0')
        {
            return pdst;
        }
    }
    return NULL;
}
char *my_strchr(char *dst, const char a)
{
    assert(dst);
    while (a != *dst)
    {
        dst++;
    }
    return dst;
}
int my_strcmp(const char *dst, const char *src)
{
    assert(dst);
    assert(src);
    int count = ;
    int len = my_strlen(dst);
    while (my_strlen(dst) > len)
    {
        return -;
    }
    while (my_strlen(dst) < len)
    {
        break;
    }
    while ((*dst == *src) && (*dst != '\0'))
    {
        dst++;
        src++;
        count++;
    }
    if (count == len)
    {
        return ;
    }
    return ;
}
void *my_memcpy(void *dst,const void *src,int size)
{
    assert(dst);
    assert(src);
    char *pdst = (char *)dst;
    char *psrc = (char *)src;
    char *p = pdst;
    while ((pdst > psrc) | (pdst < psrc))
    {
        p = "因存在内存覆盖问题，请使用my_memmove函数";
        return p;
    }
    while (size--)
    {
        *pdst++ = *psrc++;
    }
    return p;
}
void *my_memmove(void *dst, const void *src, int size)
{
    assert(dst);
    assert(src);
    char *pdst = (char *)dst;
    char *psrc = (char *)src;
    char *p = pdst;
    if (pdst>psrc)
    {
        pdst = pdst + size - ;
        psrc = psrc + size - ;
        while (size--)
        {
            *pdst-- = *psrc--;
        }
    }
    if (pdst<psrc)
    {
        while (size--)
        {
            *pdst++ = *psrc++;
        }
    }
    return p;
}