right shifting on non integer types numbers

Question

i have following code

#include <iostream>
using namespace std;
int main(){

float f=56.34f;
double d=12.34101;
cout<<(f>>1.0)<<endl;
cout<<(d>>1.0)<<endl;


return 0;
}

but it doesn't work and there is this error:

In function 'int main()': Line 7: error: invalid operands of types 'float' and 'double' to binary 'operator>>' compilation terminated due to -Wfatal-errors.

Is here allowed right shifting in C/C++ compiler? I am using visual studio 2010.

Answer 1

That's because, until C++ gets ported to quantum computers, you can't shift by half a bit.

In other words, it makes no sense for the bitshift operator >> to support floating-point operands. Yet.

Answer 2

You cannot shift non-integral types. It is illegal in C++.

If you are looking to multiply or divide by powers of two, then just do that. Shifting doesn't work like that on floating point numbers due to the way they are represented.

If you actually do want to shift the bit pattern of a float, then you'll need to do some casting, or use a union.

union
{
  float f;
  int i;
} u;
u.f = 56.34f;
u.i >>= 1;
cout << u.f << endl;

But the value you get out is totally meaningless (you aren't dividing by 2).