Question

Please consider following code:

1.

uint16 a = 0x0001;

if(a < 0x0002)
{
    // do something
}

2.

uint16 a = 0x0001;

if(a < uint16(0x0002))
{
    // do something
}

3.

uint16 a = 0x0001;

if(a < static_cast<uint16>(0x0002))
{
    // do something
}

4.

uint16 a = 0x0001;
uint16 b = 0x0002;

if(a < b)
{
    // do something
}

What compiler does in backgorund and what is the best (and correct) way to do above testing?

p.s. sorry, but I couldn’t find the better title 🙂

EDIT:

values 0x0001 and 0x0002 are only example. There coudl be any 2 byte value instead.

Thank you in advance!

Answer 1

The last example is the best code-wise, as you shouldn’t use “magic constants” in your code.

In fact, the best way would be to make b const, (edit) and use meaningful names:

uint16 currentSpeed = 0x0001; 
const uint16 cMaxSpeed = 0x0002; 

if (currentSpeed < cMaxSpeed) 
{ 
    // do something 
} 

Other than that, there is very little difference “under the bonnet” between your examples.