Discrete math is a compilation of different types of math.  My discrete math started off with something like boolean algebra.

Boolean algebra allows you to reduce statements into simpler ones.  For example:

Let a, b, and c be boolean.

(a and b) or (a and c) = a or (b and c), i.e. these two statements have the same truth values for any a, b, or c.  If (a and b) or (a and c) is false, so is a or (b and c).

It also has rules for negations:

not (a and b) = (not a) or (not b)

In programming, it makes writing if statements much more clear.

Discrete math, for me, went from boolean algebra, to proofs (forward, contrapositive, contradiction, and induction), to sets, operations, and functions.

The only application for discrete math in programming is function analysis, i.e. seeing how long a piece of code would take to run.

mikau wrote:

It does not hold a value.

Ah, but it does! It holds a binary value, the basis of life as we know it.

Yeah I meant it doesn't store a numerical value for the user.

Why the heck is it 8 bits on some compilers? I thought the purpose was to save memory for switch variables. Peculiar...

like in C++?

Last edited by mikau (2006-02-02 09:34:52)

Its not that hard to use once you know it. But it can very hard to learn sometimes.

Why the heck is it 8 bits on some compilers? I thought the purpose was to save memory for switch variables. Peculiar...

This is a bit of a complex question (pun intended).  Computers run much faster if all data is stored in whole bytes.  To understand why, you need to understand the underlying architecture, which would take me a while to describe.

Well in the case of C++, there are I believe three logical operators,  And "&&" Or, "||" and Not "!"

Really an if statement returns true if the statement is true, and false if the statement is false, but you can use simple values instead of relational opererators such as ==, >, <, etc. A variable with a value of  zero evaluates false. All others evaluate true.

If for instance you were to say:

if(5) { statement; }

it will evaluate true and always will since 5 does not equal zero, and the statement will be excecuted.

if(0) { statement; }

this will not be executed. Zero returns false.

When you use the logical operators,  you can use the "or" and "and" operaters to execute a statement if either, or only if both are true.

you could say

if(0 || 1) { statement; }

that would return true. ( "||" means or)

if (0 && 1) { statement; }

that would not return true since both must be true.

But when you say if ( x == (5 || 7)) { statement;}

I believe this is incorrect use of the or operator. The or operator is used between two expressions that are evaluated for their truth or falsity. Not their value.

maybe there is. Many computer languages hold secret techniques only known by the ninja's.

Hmm...case true eh? Pretty slick. I had thought of the rollover switch, but it seems like using a sledgehammer to open a can. Almost easier to just use a knife. But what I really need is a can opener...

<?php
function canOpener ($can)  {
    $canOpened = false;
    $args = func_get_args();
    unset ($args[0]);  //that's $can; we have that one
    
    foreach ($args as $compareTo)  {
        if ($can == $compareTo)  { $canOpened = true; }
    }
    
    return $canOpened;
}
?>

:p