I think there are two boolean type we can use bool and BOOL. What's the difference between those two?  bool contains true and false; BOOL contains TRUE and FALSE, can they be interchangeable?
121889
I saw the "new type" BOOL (YES, NO).  I read that this type is almost like a char.  For testing I did :  NSLog(@"Size of BOOL %d", sizeof(BOOL)); NSLog(@"Size of bool %d", sizeof(bool));   Good to see that both logs display "1" (sometimes in C++ bool is an int and its sizeof is 4)  So I was just wondering if there were some issues with the bool type or something ?  Can I just use bool (that seems to work) without losing speed?
75083
I am trying to make sense of these. To me a is false because the set isn't empty. Is that correct? b is true because the empty set is an element of that set. c is false because the set the empty set isn't an element, it is a subset or proper subset. d is true because the set the empty set is a member of that set. e the set the empty set is false because it is not a proper subset I think f false for the same reason g false for the same  a) ∅ ∈ {∅} b) ∅ ∈ {∅, {∅}} c) {∅} ∈ {∅} d) {∅} ∈ {{∅}} e) {∅} ⊂ {∅, {∅}} f ) {{∅}} ⊂ {∅, {∅}} g) {{∅}} ⊂ {{∅}, {∅}}  I know not all these are correct, why is my logic wrong?
25615
Can I convert a string representing a boolean value (e.g., 'true', 'false') into a intrinsic type in JavaScript?  I have a hidden form in HTML that is updated based upon a user's selection within a list. This form contains some fields which represent boolean values and are dynamically populated with an intrinsic boolean value. However, once this value is placed into the hidden input field it becomes a string.  The only way I could find to determine the field's boolean value, once it was converted into a string, was to depend upon the literal value of its string representation.  var myValue = document.myForm.IS_TRUE.value; var isTrueSet = myValue == 'true';   Is there a better way to accomplish this?
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Is there a better way to negate a boolean in Java than a simple if-else?  if (theBoolean) {     theBoolean = false; } else {     theBoolean = true; }
41729
"This sentence is false". Is this sentence true or false?   My attempt:  If this sentence were true, then what it says would be the truth , it implies that it is false which is a contradiction. if it were false then it is false that this sentence is false, hence it  is true which is also a contradiction. So this sentence can neither be true be true nor false. Is my reasoning correct?  PS: I would like to see more of such statements.
62033
I have a question about comparing a string with the empty string in Java. Is there a difference, if I compare a string with the empty string with == or equals? For example:  String s1 = "hi";  if (s1 == "")   or   if (s1.equals(""))    I know that one should compare strings (and objects in general) with equals, and not ==, but I am wondering whether it matters for the empty string.
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I am struggling to understand this. According to truth tables, if $P$ is false, it doesn't matter whether $Q$ is true or not: Either way, $P \implies Q$ is true.  Usually when I see examples of this people make up some crazy premise for $P$ as a way of showing that $Q$ can be true or false when $P$ is something outrageous and obviously untrue, such as "If the moon is made of bacon-wrapped apple-monkey carburetors, then I am a better wakeborder than Gauss."  $P$ is clearly false, but $P \implies Q$ is true no matter what the state of $Q$ is, and I don't understand why.  Are we saying "If $P$ is false, then all bets are off and $Q$ can be anything, either true or false, and not contradict our earlier claim, and if it isn't false, it must be true"?  Otherwise why can't we say that if $P$ is false, then we can't make any claims one way or the other on whether or not it implies anything at all?
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In C# are the nullable primitive types (i.e. bool?) just aliases for their corresponding Nullable&lt;T&gt; type or is there a difference between the two?
44530
True or False  $A - C = B - C $ if and only if $A \cup C = B \cup C$   I am in an introduction to proofs class.  I think this is a true statement. I have began the proof and realize I have to do this both directions.  I am stuck on the second part of the proof.  Assume $A - C = B - C$ Let $x \in A$ then $x \in A$ but $x\notin C$ By the assumption $x \in B - C$ then $x \in B$ and $x\notin C$  If $x \in A$ then $x \in A \cup C$.  If $x\in B$ then $x \in B \cup C$. Therefore,  $A \cup C = B\cup C$.   Assume $A \cup C = B \cup C$. Let $x \in A \cup C$. Then $x \in A$ or $x\in C$.  If $x \in A$ then $x \in A - C$  If $x\notin A$ then $x \in C$.   This is where I get stuck... I know I am trying to show $A-C = B-C$ for the second part but I don't know how to get there... Am I on the right track?
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Am unsure (leaning more towards no): true P and true C is valid, false P and false C is valid, True P and false C is invalid, how about false P and true C?  P= Premises; C= Conclusion.  People who says.. Yes, it is valid, I would like to hear some answers for   How can we derive the truth out of falsehood?  If we can, then True P - False C is valid too (tell me why it is invalid?).
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Obviously since A → C and B → D then if A v B one of C or D must be true.   My only idea is v must be introduced, but how would I use subproofs to show one of A /\ C or B /\ D is never false if A v B?
7945
What is the difference between &gt;&gt; and &gt;&gt;&gt; in verilog/system verilog? I know that == tests for only 1 and 0, while === tests for 1, 0, X, Z. So how is that similar to the shift operator?
72612
I'm interested to know how people have, or would construct an interface which simplifies constructing logical boolean conditions? (Yes, it's a database query builder) In my mind a bad interface has them typing lots of AND, NOT IN, OR keywords etc. Or else has a million combo boxes.  I'm wondering if anyone has a good example I could glean ideas from? Or some suggestions?  At the moment I'm considering a split screen with a grid for composing the query and a canvas to display a visual representation of the sets of conditions and how they overlap etc. Like a Venn Diagram. This still gives me a problem with the usability/intuitiveness of the controls on the grid.  EDIT:  I'm very interested in ideas which simplify it for less technical users. However, ideas for a version of the UI for advanced users are very helpful as well.
5199
Is ∅ equivalent to {∅}? I think they are, but I am not sure? If anyone could clarify, that would be great. Thank you!
40162
Please demonstrate how the ternary operator works with a regular if/else block. Example:  Boolean isValueBig = value &gt; 100 ? true : false;     Exact Duplicate:
84865
What's the difference between eq, eql, equal and equalp, in Common Lisp?  I understand that some of them check types, some of them check across types an all that, but which is which?  When is one better to use than the others?
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How does one add a field to an ArcGIS feature class with a boolean data type? That is an attribute where the allowed value is only one of a pair such as 1/0, Yes/No, On/Off, Present/Not-present, etc.   A boolean data type is not available in the Data Type pick-list.