Fill C array with smaller C arrays http://coliru.stacked-crooked.com/a/de90378788620cf2

fill_array.cpp

#include <iostream>
#include <cstring>

int main()
{
    float* biga = new float[6];
    
    float* a = new float[3];
    a[0] = 1.0f;
    a[1] = 1.0f;
    a[2] = 1.0f;
    
    std::memcpy(&biga[0], &a[0], sizeof(float) * 3);
    
    float* b = new float[3];
    b[0] = 2.0f;
    b[1] = 2.0f;
    b[2] = 2.0f;
    
    std::memcpy(&biga[3], &b[0], sizeof(float) * 3);
    
    
    for(size_t i = 0; i < 6; ++i)
    {
        std::cout << biga[i] << ' ';   
    }
    std::cout << '\n';
    
}