Implementation of memcpy in C language

One .memcpy Introduce

void* memcpy ( void* dest, const void* src, size_t num );

size_t num --- Unit is byte （ How many bytes to copy ）

void* Can receive any type of address , But it cannot be dereferenced or ++--

Be careful ：memcpy Cannot overlap copies

Two .memcpy Use

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>


int main()
{
    int i = 0;
    int arr1[] = { 1,2,3,4,5 };
    int arr2[5] = { 0 };
    memcpy(arr2, arr1, sizeof(arr1));
    for (i = 0; i < 5;i++)
    {
        printf("%d\n", arr2[i]);
    }
    return 0;
}

3、 ... and .memcpy The implementation of the

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<assert.h>

void* my_memcpy(void* dest, const void* src, size_t num)
{
	void* ret = dest;
	assert(dest != NULL);
	assert(src != NULL);
	while (num--)
	{
		*(char*)dest = *(char*)src;
		(char*)dest+=1;
		(char*)src+=1;
	}
	return ret;
}
int main()
{
	int i = 0;
	int arr1[] = { 1,2,3,4,5 };
	int arr2[5] = { 0 };
	my_memcpy(arr2, arr1, sizeof(arr1));
	for (i = 0; i < 5;i++)
	{
		printf("%d\n", arr2[i]);
	}
	return 0;
}