boolean

How to serialize Nullable<bool> ?

I want to serialize a nullable bool simply by converting it to a string public static string SerializeNullableBoolean(bool? b) { if (b == null) { return "null or -1 or .."; // What to return here? } else { return b.ToString(); } } What is the most appr...

Understanding a boolean on DirectoryInfo.Exists

Hi everyone, var fileOpen = new OpenFileDialog(); var clickedOk = fileOpen.ShowDialog(); if (!((bool) clickedOk)) return; var path = fileOpen.FileName; var diPath = new DirectoryInfo(path); var fiPath = new FileInfo(path); Debug.WriteLine(diPath.Exists); I am just wondering why diPath.Exists is false in this case? Since the user has...

Oracle's lack of a Bit datatype for table columns.

Hi Everyone, I work as a developer on a small development team, and something has annoyed me to the point where I have decided to act... Oracle does not support a Bit datatype - or indeed anything else that makes obvious sense in true/false scenarios. Undeterred however, before I joined the team my forebears decided to use char(1) fiel...

boolean in java: what am I doing wrong?

Hello, I am trying to make my boolean value work. I am new at programming java so I must be missing something simple. I am trying to make it so that if one of the tire pressures is below 35 or over 45 the system outputs "bad inflation" For class I must use a boolean which is what I tried. I cant figure out why this isnt working. No matt...

Forcing value to boolean: (bool) makes warning, !! doesnt.

I like (bool) way more, but it generates warnings. How do i get rid off the warnings? I have code like: bool something_else = 0; void switcher(int val = -1){ if(val != -1){ something_else = (bool)val; }else{ something_else ^= 1; } } Should i just do it like everyone else and use '!!' or make it somehow hi...

In MATLAB can I convert a java boolean to a MATLAB logical?

In MATLAB I'm using a couple of java routines I've written to interface with a MyQSL database. One routine returns a boolean value result <1x1 java.lang.Boolean> >> result result = true When I then use it in a conditional statement I get an error message. >> if result, disp('result is true') end ??? Conversion to logical from java....

In PHP can I check a boolean on a function call?

I have a function which checks the passed value and returns false or true, if false I want it to add something to an array. The code I've written is below. if(!check_input($_POST['username'])){ $errors[] = "Username"; } Right now it adds to my array anyway, regardless of what is entered in the form. Is the way I've written...

How to organize infinite while loop in SQL Server ?

I want to use infinite WHILE loop in SQL Server 2005 and use BREAK keyword to exit from it on certain condition. while true does not work, so I have to use while 1=1. Is there a better way to organize infinite loop ? I know that I can use goto, but while 1=1 begin .. end looks better structurally. ...

Dynamically evaluating simple boolean logic in Python

I've got some dynamically-generated boolean logic expressions, like: (A or B) and (C or D) A or (A and B) A empty - evaluates to True The placeholders get replaced with booleans. Should I, Convert this information to a Python expression like True or (True or False) and eval it? Create a binary tree where a node is either a bool or ...

Should programmers use boolean variables to "document" their code?

I'm reading McConell's Code Complete, and he discusses using boolean variables to document your code. For example, instead of: if((elementIndex < 0) || (MAX_ELEMENTS < elementIndex) || (elementIndex == lastElementIndex)){ ... } He suggests: finished = ((elementIndex < 0) || (MAX_ELEMENTS < elementIndex)); repeatedEntry = (...

How to make a boolean variable switch between true and false every time a method is invoked?

Hi, I am trying to write a method that when invoked, changes a boolean variable to true, and when invoked again, changes the same variable to false, etc. For example: call method -> boolean = true -> call method -> boolean = false -> call method -> boolean = true So basically, if (a = false) { a = true; } if (a = true) { a = false; }...

How do I call a static bool method in main.m

This is Objective-C, in Xcode for the iPhone. I have a method in main.m: int main(int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; //I want to call the method here// int retVal = UIApplicationMain(argc, argv, nil, nil); [pool release]; return retVal; } static BOOL do_it_all () { //code here// } ...

php boolean help

Hello, I seem to have a small problem, in the code below $a_trip is always true, even if $trip!= $admin_trip. Any idea why? if($trip == $admin_trip) $a_trip = true; if($a_trip == true) $trip = ("~::##Admin##::~"); ...

Is there a boolean literal in SQLite?

I know about the boolean column type, but is there a boolean literal in SQLite? In other languages, this might be true or false. Obviously, I can use 0 and 1, but I tend to avoid so-called "magic numbers" where possible. From this list, it seems like it might exist in other SQL implementations, but not SQLite. (I'm using SQLite 3.6.1...

Naming booleans

If I only want to check if something is impossible or not (i.e., I will not be using something like if(possible)), should I name the boolean notPossible and use if(notPossible) or should I name it possible and use if(!possible) instead? And just to be sure, if I also have to check for whether it is possible, I would name the boolean pos...

Why am I getting an error when return TRUE/FALSE to type Boolean?

I wrote the following code: import java.lang.*; import DB.*; private Boolean validateInvoice(String i) { int count = 0; try { //check how many rowsets ResultSet c = connection.DBquery("select count(*) from Invce i,cust c where tranid like '"+i+"' and i.key = c.key "); while (c.next())...

Why is the Objective-C Boolean data type defined as a signed char?

Something that has piqued my interest is Objective-C's BOOL type definition. Why is it defined as a signed char (which could cause unexpected behaviour if a value greater than 1 byte in length is assigned to it) rather than as an int, as C does (much less margin for error: a zero value is false, a non-zero value is true)? The only re...

Why .NET Boolean has TrueLiteral and TrueString?

Why in Boolean type there are two fields with the same value? internal const int True = 1; internal const int False = 0; internal const string TrueLiteral = "True"; internal const string FalseLiteral = "False"; and public static readonly string TrueString; public static readonly string FalseString; static Boolean() { TrueString ...

Why am I getting such random results when checking DNS?

The code is as follows: $domain = "fosajfjdkgdajfhsd.com"; $check1 = checkdnsrr($domain, "MX"); $check2 = checkdnsrr($domain, "A"); $check3 = (checkdnsrr($domain, "MX") || checkdnsrr($domain, "A")); $check4 = !(checkdnsrr($domain, "MX") || checkdnsrr($domain, "A")); die("{$check1} - {$check2} - {$check3} - {$check4}"); However when I ...

Is There an Easy Way to Convert a Boolean to an Integer?

I am new to scala and I am finding the need to convert a boolean value to an integer. I know i can use something like if (x) 1 else 0 but I would like to know if there is a preferred method, or something built into the framework (ie toInt()) ...