I got two structs. Some parts of the two structs have exactly the same element type (and name).
How can I assign one with another's value?
as below demonstrated:
struct X
{
struct {
int a = 0;
int b = 0;
} z;
int c = 0;
};
struct Y
{
int a = 0;
int b = 0;
};
int main()
{
X x{ 1,2,3 };
Y y;
// I know i can do:
y.a = x.z.a;
y.b = x.z.b;
// Is there a simple way like:
// y = x.z;
}
I looked into memcpy but in my real case, the X is much more complicated and dynamic in length. memcpy looks not quite help for me.
Is there a simple way like: y = x.z; ?
Y is not same as decltype(X::z). Therefore, it is not possible without any further tweaks.
One way is, to provide copy assignment operator overload for Y, which can accept the decltype(X::z) type, and does the assignment to Y.
struct Y
{
int a = 0;
int b = 0;
using Z_t = decltype(X::z);
Y& operator=(const Z_t& z)
{
a = z.a;
b = z.b;
return *this;
}
};
Now you can write
X x{ 1,2,3 };
Y y;
y = x.z;