Member Avatar for nobi

Hi,

MyByte is byte that could contain binary value between 0000 and 1111

int sum = 0;

                for (int i = 0; i <= 3; i++)

                {

                    if((MyByte & 2^i ) == 1)

                        sum += 2^i;

                }

What will be the value of SUM at the end of this loop ?

tnx,

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  • Latest Post Latest Post by invisal
Member Avatar for sarehu

Why don't you try running the program yourself? Sheesh.

Member Avatar for nobi

I know what will be the results. its a general question, is there an equation that can express the value of SUM after the loop in dependence with MyByte value?

Member Avatar for sarehu

You could represent it with a 15-degree polynomial.

Here's a hint: I think it is meant for ^ be an exponentiation operator, not a bitwise xor operator.

Member Avatar for invisal

If ^ is a exponentiation operator, then the sum will be equal to the MyByte . If the ^ is a XOR operator, then the sum depend on MyByte Since:

[B]ABCD[/B] represents for MyByte binary.
ABCD & (0010 ^ 0000) = 00C0 (it can be 0 or 2)
ABCD & (0010 ^ 0001) = 00CD (it can be 0, 1, 2, 3)
ABCD & (0010 ^ 0010) = 0000
ABCD & (0010 ^ 0011) = 000D (it can be 0 or 1)

As you can see:

  • If MyByte is a even number, then sum must be equal 0.
  • If MyByte is an odd number, then sum must be equal to 1 or 4
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