The documentation for SQL Server Float says

Approximate-number data types for use with floating point numeric data. Floating point data is approximate; therefore, not all values in the data type range can be represented exactly.

Which is what I expected it to say. If that is the case though why does the following return 'Yes' in SQL Server

DECLARE @D float
DECLARE @E float

set @D = 0.1
set @E = 0.5

IF ((@D + @D + @D + @D +@D) = @E)
 BEGIN
 PRINT 'YES'
 END 
ELSE
 BEGIN
 PRINT 'NO'
 END 

but the equivalent C++ program returns "No"?

#include <iostream>

using namespace std;

int main()
{
float d = 0.1F;
float e = 0.5F;

if((d+d+d+d+d) == e)
 {
 cout << "Yes";
 }
else
 {
 cout << "No";
 }
}