Do not use library functions, written by yourself (strlen, strcpy, strcmp, strcat, memcmp, memcpy, Memmove)

function to find the length of a string
int My_strlen (const char* PSTR)
{
ASSERT (PStr! = NULL);
int length = 0;
while (*pstr++! = ')
{
length++;
}
return length;
}
String copy function
char* my_strcpy (char* strdest, const char* STRSRC)
{
ASSERT (strdest = null && STRSRC! = null);
char* pDest = strdest; Protection parameters
Const char* PSRC = STRSRC;
while (*psrc! = ')
{
*pdest++ = *psrc++;
}
*pdest = ' + ';
return strdest;
}
string comparison function
int my_strcmp (const char* strdest, const char* STRSRC)
{
ASSERT (strdest = null && STRSRC! = null);
if (*strdest = = ' &&*strsrc '! = ') '
{
return 0;
}
Const char* pDest = strdest;
Const char* PSRC = STRSRC;
int result = 0; Used to record comparison results
while (*pdest! = ' | | | *psrc! = ') '
{
if (result = *pdest-*psrc)! = 0)
{
Break
}
pdest++;
psrc++;
}
if (Result > 0)
{
result = 1;
}
else if (result<0)
{
result =-1;
}
return result;
}
String Join function
char* My_strcat (char* strdest, char* strsrc)
{
ASSERT (strdest = null && STRSRC! = null);
char* pDest = strdest;
char* PSRC = strsrc;
while (*pdest! = ')
{
pdest++;
}
while (*psrc! = ')
{
*pdest++ = *psrc++;
}
*pdest = ' + ';
return strdest;
}

/Memory Comparison function
int my_memcmp (void* src1, void* src2, int len)
{
ASSERT (SRC1 = null && SRC2! = null);
Const char* PSRC1 = (char*) src1;
Const char* PSRC2 = (char*) src2;
while (len--> 0)
{
if (*psrc1++! = *psrc2++)
{
Return *psrc1 < *PSRC2? -1:1;
}
}
return 0;
}

Memory copy function
void* my_memcpy (void* dest, const void* SRC, size_t count)
{
ASSERT (dest! = NULL && src! = null);
char* pDest = (char*) dest;
Const char* PSRC = (const char*) src;
while (count--> 0)
{
*pdest++ = *psrc++;
}
return dest;
}

Memory Move function
void* My_memmove (void* dest, void* src, size_t count)
{
ASSERT (dest! = NULL && src! = null);
char* pDest = (char*) dest;
Const char* PSRC = (char*) src;
if (pSrc >= pDest | | pDest >= (PSRC + count))
{

while (count--> 0)
{
*pdest++ = *PSRC;
}
}
Else
{
while (count--> 0)

{

* (PDest + count) = * (PSRC + count);
}
}
*pdest = ' + ';
return dest;
}

Do not use library functions, written by yourself (strlen, strcpy, strcmp, strcat, memcmp, memcpy, Memmove)