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Difference between signed / unsigned char [duplicate]
...w that the difference between a signed int and unsigned int is that a bit is used to signify if the number if positive or negative, but how does this apply to a char ? How can a character be positive or negative?
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How many database indexes is too many?
I'm working on a project with a rather large Oracle database (although my question applies equally well to other databases). We have a web interface which allows users to search on almost any possible combination of fields.
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Copy / Put text on the clipboard with FireFox, Safari and Chrome
...xt you can quickly generate a textArea, modify the text in the box, select it, copy it, and then delete the textArea. In most cases this textArea wont even flash onto the screen.
For security reasons, browsers will only allow you copy if a user takes some kind of action (ie. clicking a button). On...
Parse string to DateTime in C#
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DateTime.Parse() will try figure out the format of the given date, and it usually does a good job. If you can guarantee dates will always be in a given format then you can use ParseExact():
string s = "2011-03-21 13:26";
DateTime dt =
DateTime.ParseExact(s, "yyyy-MM-dd HH:mm", CultureInfo...
Reorder / reset auto increment primary key
I have a MySQL table with an auto increment primary key. I deleted some rows in the middle of the table. Now I have, for example, something like this in the ID column: 12, 13, 14, 19, 20. I deleted the 15, 16, 17 and 18 rows.
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Where to put include statements, header or source?
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Only put includes in a header if the header itself needs them.
Examples:
Your function returns type size_t. Then #include <stddef.h> in the header file.
Your function uses strlen. Then #include <string.h> in the source file.
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What is [Serializable] and when should I use it?
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What is it?
When you create an object in a .Net framework application, you don't need to think about how the data is stored in memory. Because the .Net Framework takes care of that for you. However, if you want to store the contents ...
Difference between Covariance & Contra-variance
... are properties of a mapping function that associates one member of a set with another. More specifically, a mapping can be covariant or contravariant with respect to a relation on that set.
Consider the following two subsets of the set of all C# types. First:
{ Animal,
Tiger,
Fruit,
Bana...
Encrypt Password in Configuration Files? [closed]
...to encrypt and decrypt a text by using a password.
This basically means initializing a javax.crypto.Cipher with algorithm "AES/CBC/PKCS5Padding" and getting a key from javax.crypto.SecretKeyFactory with the "PBKDF2WithHmacSHA512" algorithm.
Here is a code example (updated to replace the less secur...
Getting the application's directory from a WPF application
I found solutions for Windows Forms with AppDomain but what would be the equivalent for a WPF Application object?
8 Answe...