How to rewrite numbers from first array to second array?

Answer 1

Even easier method, if you are on a newer compiler :

#include<algorithm>
int main()
{
int a1[5],a2[5];
std::copy(a1,a1+5,a2);
for( int i : a2 ) cout<<i;
}

Note that a2 must have a size that can hold the number of elements specified for copying.

Answer 2

you mean transfer elements from array to another?
for(i=0;I<array1.length;i++)
{array2[I]=array1[I]}