memcpy.cpp

#include <stdio.h>
#include <iostream>
#include <string.h>

struct Item {
    int i;
    char buf1[10];
    char buf2[20];    
};

int main()
{
    Item item;
    std::cout << "Start of struct " << (&item) << std::endl;
    std::cout << "Start of i in struct " << &(item.i) << std::endl;
    std::cout << "Start of buf1 in struct " << &(item.buf1) << std::endl;
    std::cout << "Start of buf2 in struct " << &(item.buf2) << std::endl;
    
    int a = 10;
    char* pBuf1 = new char[20];
    strncpy(pBuf1, "test123", 10);
    char* pBuf2 = new char[20];
    strncpy(pBuf2, "123test", 10);
    
    memcpy(&item.i, &a, sizeof(a));
    memcpy(&item.buf1, pBuf1, sizeof(item.buf1));
     //memcpy(&item+4, pBuf1, sizeof(item.buf1)); // doesn't work because +4 works as &item+4*sizeof(item)
    memcpy(&item.buf2, pBuf2, sizeof(item.buf2));
        
    std::cout << item.i << std::endl;
    std::cout << item.buf1 << std::endl;
    std::cout << item.buf2 << std::endl;
    
    Item item2;
    memcpy(&item2, &item, sizeof(Item));
    
    std::cout << item2.i << std::endl;
    std::cout << item2.buf1 << std::endl;
    std::cout << item2.buf2 << std::endl;
    
    return 0;
   
}