strcmp/strncpy/strncat模拟实现

char* my_strncat(char* dest, const char* src, size_t count)
{
char* ret = dest;
while (dest++);
dest--;
while (count--)
if (!(*dest++ = *src++))
return ret;
*dest = '\0';
return ret;
}
int main()
{
char arr1[30] = "hello";
char arr2[] = "world";
strncat(arr1, arr2, 3);
my_strncat(arr1, arr2, 3);
return 0;
}
char* my_strncpy(char* dest, const char* src, size_t count)
{
char* ret = dest;
while (count && (*dest++ = *src++))
{
count--;
}
if (count)
{
while (--count)
{
*dest++ = '\0';
}
}
return ret;
}
int main()
{
char arr1[10] = "abcefsdd";
char arr2[] = "hello";
//strncpy(arr1, arr2, 4);
my_strncpy(arr1, arr2, 8);
return 0;

}
int my_strcmp(const char* str1, const char* str2)
{
assert(str1 && str2);
while (*str1 == *str2)
{
if (*str1 == '\0')
return 0;
str1++;
str2++;
}

return (str1-str2);

}