My personal guideline is: an exception is thrown when a fundamental assumption of the current code block is found to be false. Example 1: say I have a function which is supposed to examine an arbitrary class and return true if that class inherits from List<>. This function asks the question, “Is this object a … Read more
What is NP? NP is the set of all decision problems (questions with a yes-or-no answer) for which the ‘yes’-answers can be verified in polynomial time (O(nk) where n is the problem size, and k is a constant) by a deterministic Turing machine. Polynomial time is sometimes used as the definition of fast or quickly. … Read more
The credit/debit card number is referred to as a PAN, or Primary Account Number. The first six digits of the PAN are taken from the IIN, or Issuer Identification Number, belonging to the issuing bank (IINs were previously known as BIN — Bank Identification Numbers — so you may see references to that terminology in … Read more
A magic number is a direct usage of a number in the code. For example, if you have (in Java): public class Foo { public void setPassword(String password) { // don’t do this if (password.length() > 7) { throw new InvalidArgumentException(“password”); } } } This should be refactored to: public class Foo { public static … Read more
While each generated GUID is not guaranteed to be unique, the total number of unique keys (2128 or 3.4×1038) is so large that the probability of the same number being generated twice is very small. For example, consider the observable universe, which contains about 5×1022 stars; every star could then have 6.8×1015 universally unique GUIDs. … Read more
OK, you’re defining the problem to where it would seem there is not much room for improvement. That is fairly rare, in my experience. I tried to explain this in a Dr. Dobbs article in November 1993, by starting from a conventionally well-designed non-trivial program with no obvious waste and taking it through a series … Read more
First and foremost, the “pass by value vs. pass by reference” distinction as defined in the CS theory is now obsolete because the technique originally defined as “pass by reference” has since fallen out of favor and is seldom used now.1 Newer languages2 tend to use a different (but similar) pair of techniques to achieve … Read more
Big List of Resources: A Nanopass Framework for Compiler Education ¶ Advanced Compiler Design and Implementation $ An Incremental Approach to Compiler Construction ¶ ANTLR 3.x Video Tutorial Basics of Compiler Design Building a Parrot Compiler Compiler Basics Compiler Construction $ Compiler Design and Construction $ Crafting a Compiler with C $ Crafting Interpreters [Compiler … Read more
A parameter is the variable which is part of the method’s signature (method declaration). An argument is an expression used when calling the method. Consider the following code: void Foo(int i, float f) { // Do things } void Bar() { int anInt = 1; Foo(anInt, 2.0); } Here i and f are the parameters, … Read more
Breadth vs Depth; think in terms of a tree of references with your object as the root node. Shallow: The variables A and B refer to different areas of memory, when B is assigned to A the two variables refer to the same area of memory. Later modifications to the contents of either are instantly … Read more