Difference between MySQL IS NOT NULL and != ''
Is there any difference between MySQL IF (myText IS NOT NULL) THEN and IF (myText != '') THEN ...
operators
Implicit conversion while using += operator?
Conside the following code: int main() { signed char a = 10; a += a; // Line 5 a = a + a; return 0; } I am getting this warning at Line 5: d:\codes\operator cast\operator cast\test.cpp(5) : warning C4244: '+=' : conversion from 'int' to 'signed char', possible loss of data Does this mean that += operato...
Does any language use "=/=" for denoting the not-equal operator
Does any programming language use =/= for not-equal? Are there any lexical difficulties for scanners to recognize such an operator? Or was it the case historically? [Note: this is NOT a homework question. I'm just curious.] ...
Why do C#'s binary operators always return int regardless of the format of their inputs?
If I have two bytes a and b, how come: byte c = a & b; produces a compiler error about casting byte to int? It does this even if I put an explicit cast in front of a and b. Also, I know about this question, but I don't really know how it applies here. This seems like it's a question of the return type of operator &(byte operand, by...
Are operands inside an expression promoted to larger types according to the following rules?
If numeric expression contains operands (constants and variables) of different numeric types, are operands promoted to larger types according to the following rules: if operands are of types byte, sbyte, char, short, ushort, they get converted to int type If one of the operands is int, then all operands are converted to int if expressi...
Why is my operator<< overloading not working?
Error: ..\Record.cpp: In function `std::ostream& operator<<(std::ostream&, Record&)': ..\Record.cpp:83: error: no match for 'operator<<' in 'out << Record::date()()' Record.cpp: /* * Record.cpp * * Created on: Jun 13, 2010 * Author: DJ */ #include <iostream> #include "Record.h" using std::string; using std::istream; using...
Should you format operator<< for classes?
As in, should the operator>> match the operator<< ? Database Example: If the operator>> reads in something of the following format: 2 Joe 500 20 1 Bob 250 30 0 should the operator<< output that? Or something like this: Record: 1/2 Name: Joe Balance: 500 Transactions: 20 Premium Account: Yes And then have a separate writeFile() fu...
why do we shift bits while checking ip address
I have a range of ip addresses ,and I need to check that my client which accesses my application falls in that range. I went thru few articles, and they shift bits after splitting the IP for instance 127.0.0.1 is splitted after the '. ' and after splitting we get an array of 4 elements, and each of it is shifted element 1 >> 24; etc ...
+\ operator in Python
What does the +\ operator do in Python? I came across this piece of code - rows=urllib2.urlopen('http://ichart.finance.yahoo.com/table.csv?'+\ 's=%s&d=11&e=26&f=2006&g=d&a=3&b=12&c=1996'%t +\ '&ignore=.csv').readlines( ) and can't find any references that explain it. ...
C Operator precedence (x[i] = --i)
Possible Duplicate: Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc) I am wondering if x[i] = --i is defined by C standard. I tested it with g++ and it looked like x[i] was resolved before i was decreased. Is this a standard? And can you give me some more information about how is this evaluated. ...
Operator Precedence in C
Possible Duplicate: Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc) Hi, if x = 10, y=11 then, can anyone please explain why int temp = x++ + ++y + x++; then, temp has a value: 33 but x = x++ + ++y + x++; then, x has value: 34 and when x = ++x + ++y + x++ then, x has value: 35 Com...
heroku Postgres error - operator does not exist timestamp without timezone = integer
I am using the following code in my controller: @monday = (Time.now).at_beginning_of_week @friday = 5.days.since(@monday)-1.second @sent_emails = ContactEmail.all(:conditions => ['date_sent >= ? and date_sent <= ?', @monday, @friday]) Although it works fine on my local sqlite, I have an "operator does not exist timestamp witho...
C++ multiple operator overloads for the same operator
I know I can answer this question easily for myself by generatin the code and see if it compiles. But since I couldn't find a similar question, I thought it's knowledge worth sharing. Say I am overloading the + operator for MyClass. Can I overload it multiple times. Different overload for different types. Like this: class MyClass{ ... ...
What is => operator in this code
I am using ThreadPool with the follwoing code:- ThreadPool.QueueUserWorkItem (o => MyFunction() ); I am not sure what does o=> does in this code. Can anyone help me out. ...
Ruby comparison operators? == vs. ===
What's the difference between == and ===? Which one should you use when? ...
What type of variable do I use to store mathematical operator?
I'm trying to put buttons that have operators on them, like / * +, etc. I want to store the operator in such a way that I can use it in an expression, like 1 var 2 = 8 I would like to avoid having to use a different method for each operator, so an operator var would be my best option, I think. Objective-C for iPhone ...
Is there a C# IN operator?
In SQL, you can use the following syntax: SELECT * FROM MY_TABLE WHERE VALUE_1 IN (1, 2, 3) Is there an equivalent in C#? The IDE seems to recognise "in" as a keyword, but I don't seem to be able to find any information on it. So, is it possible to do something like the following: int myValue = 1; if (myValue in (1, 2, 3)) // D...
How to create an operator for deep copy/cloning of objects in Ruby?
I would like to achieve the following by introducing a new operator (e.g. :=) a := b = {} b[1] = 2 p a # => {} p b # => {1=>2} As far as I understand, I need to modify the Object class, but I don't know what to do in order to get what I want. require 'superators' class Object superator ":=" operand # update, must be: superator ":=...
Pass in an Operator
Is there any way to pass in an operator in VB.NET? I'm looking to reduce my lines of code and for two functions there is literally only an operator that is different. For example, I have two functions, Darken and Lighten. I'd like to get to a single function with as little code as possible. The only difference are Greater Than and Less ...
When should I use the IN operator instead of multiple OR operators in MySQL?
I need to select some records from a table where a column value is equal to any of the values in a list. This can be done using either IN operator (like WHERE column IN (v1, v2, ...)) or multiple OR operators (like WHERE column = v1 OR column = v2, ...). When should I use either of these ways? ...