Simple question

Ok, I'm having some serious issues with Tutorial 2 and the whole ! and && with 0's and 1's. I got a 100% on the quiz but I don't even know how i did the evaluate this code

Code:

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!(1&&(1||0));

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Please help, I'm utterly confused. I understand the &&, !, and ||. I know Java well but this is just wierd to me.

Code:

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! (  1  && (  1 || 0  ) );

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Starting with the inner most parenthesis. TRUE OR FALSE is TRUE, TRUE AND TRUE is TRUE, NOT TRUE is FALSE.

Ok I think I get it. One last question, if for instance I was typing a code and wanted an if statement such as..

Code:

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if !(x==1 || x==0)

{
//do a bunch of nonsense herer
}

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Would i recive a 1? I understand how to figure it out now though. Thanks for that.

1 = true
0 = false

so the conditional is equivalent to:

Code:

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!(  true && (true||false)  );

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Quote:

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Originally Posted by mithrillegolas

Ok I think I get it. One last question, if for instance I was typing a code and wanted an if statement such as..

Code:

---


if (!(x==1 || x==0))

{
//do a bunch of nonsense herer
}

---

Would i recive a 1?

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Well, with the outer parenthesis to make the syntax correct and assuming at least one of those comparisons is true, then the result would be false. If x didn't equal 1 and x didn't equal 0, then the result would be true.

Quote:

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Would i recive a 1?

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You wouldn't receive anything.

Quote:

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Originally Posted by 7stud

You wouldn't receive anything.

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Well... he might receive a mild shock when he realizes it doesn't compile. ;)

Errr, ok. I get it, I was more referring to the fact of 1 and 0 being pre-defined and we can't touch them. But that was a stupid assumption. I understand now.

If you want to see what the result of a conditional is, you can always display it:

Code:

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int x = 10;
cout<<(x==1 || x==0)<<endl;

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it might also help by thinking of how logic gates work. the 8 basic logic operations (2 unary and 6 binary) implemented as inline functions would be:

Code:

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inline
bool
relay(bool a)
{
        return a;
}

inline
bool
not(bool a)
{
        return !a;
}

inline
bool
and(bool a, bool b)
{
        return a & b;
}

inline
bool
or(bool a, bool b)
{
        return a | b;
}

inline
bool
xor(bool a, bool b)
{
        return a ^ b;
}

inline
bool
nand(bool a, bool b)
{
        return not(and(a, b));
}

inline
bool
nor(bool a, bool b)
{
        return not(or(a, b));
}

inline
bool
xnor(bool a, bool b)
{
        return not(xor(a, b));
}

/* eg: */

int
main(void)
{
        /* !(1&&(1||0)) */
        cout << nand(1, or(1, 0)) << endl;
}

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also, by memorizing their truth tables and learning boolean algebra you will be able to verify and simplify boolean expressions with greater ease.