This is down to changes that were made for new versions of ZPE.
A condition is a rule which must be met. For instance, a computer may only be switched on if the power switch is on at the wall. This is a simple condition.
false, but more complex conditions also return these as results.
There are several operators that can be used:
|Symbol||Name||Returns true when|
|<=||Less than or equal to||
|>=||Greater than or equal to||
|!=||Not equal to||
These operators are easy to use:
var x = 5; var y = 7; var z = 0; z = x < y; alert(z); z = x > y; alert(z); z = x <= y; alert(z); z = x >= y; alert(z); z = x == y; alert(z); z = x != y; alert(z); z = x === y; alert(z); z = x !== y; alert(z);
AND and OR are based on AND gates and OR gates in computer hardware.
AND requires that two conditions are true to return true.
The following is a truth table for AND:
|P||Q||P AND Q|
&&. The following is an example using AND in a condition:
var r = false; p = true; q = false; r = true; result = p && q; alert(result); result = p && r; alert(result);
OR requires that one of the two conditions is true to return true.
The following is the truth table for OR:
|P||Q||P OR Q|
||. The following is an example using OR in a condition:
var r = false; p = false; q = false; r = true; result = p || q; alert(result); result = p || r; alert(result);
The final type of logical operator is the NOT operator. The truth table following shows how NOT performs.
! operator. Putting a NOT operator in front of
a boolean value will invert it. The following is a condition that uses
the NOT operator to flip the value of a boolean value:
var x = false; var y = true; alert(!x); alert(!y);
A key law in logic is De Morgan's Law. This law shows:
!(A && B)==
!A || !B
!(A || B)==
!A && !B
The truth table for
!(A && B) and
!A || !B is as follows:
|A||B||A && B||!(A && B)||!A || !B|
var A = true; var B = false; alert(!(A && B)); alert(!A || !B);
Now the truth table for
!(A || B) and
!A && !B is as follows:
|A||B||A || B||!(A || B)||!A && !B|
var A = true; var B = false; alert(!(A || B)); alert(!A && !B);
S1s and S2s really enjoyed the lesson on cybercrime using the lesson on How to Rob A Bank on… https://t.co/MxjDYE2JFu
8 months ago
S2s doing really well in hardware test! Also really enjoying doing tests electronically rather than on paper.… https://t.co/ritdfcW6Mw
8 months ago
S1 and S2 pupils listing input and output devices and giving answers such as keyboard and mouse but there were also… https://t.co/dGxDkYqFxo
9 months ago