Float point number simple arithmetic.

[Mulligan]

Having such a simple `c` program:

#include <stdio.h>
    #include <float.h>
    
    int main( void ) {
    		float fl1 = 0.1;
    		
    		// Set precision to 24 bits
    		_control87(_PC_24, MCW_PC);
    
    		printf( "fl1: %.10f\n", fl1 );		
    		printf( "fl1*fl1: %.10f\n", fl1*fl1 );
    }

and compiling it like that:

cl /W4 /Od /arch:IA32 teset1.c

gives me:

fl1: 0.1000000015
fl1*fl1: 0.0100000007

Can someone please explain me why does multiplying the `db1` variable returns

0.0100000007

instead of

0.0100000003

as expected?

PS.

I know that assigning the `0.1` value to the `float` makes it *truncated* from `double` to `float` but anyhow `0.1000000015 x 0.1000000015` results in **`0,01000000030000000225`** as I've checked in the *Windows Programmer Calculator*