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What is your favorite C programming trick? [closed]
...
C99 offers some really cool stuff using anonymous arrays:
Removing pointless variables
{
int yes=1;
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
}
becomes
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR...
Objective-C : BOOL vs bool
..., you can assume that BOOL is a char. You can use the (C99) bool type, but all of Apple's Objective-C frameworks and most Objective-C/Cocoa code uses BOOL, so you'll save yourself headache if the typedef ever changes by just using BOOL.
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Repeat string to certain length
... that need to be // in Python 3? Or dropping the +1 and using an explicit call to a ceiling function would suffice. Also, a note: the string generated actually has an extra repetition when it divides evenly; the extra gets cut off by the splice. That confused me at first.
– jpm...
How does deriving work in Haskell?
Algebraic Data Types (ADTs) in Haskell can automatically become instances of some typeclasse s (like Show , Eq ) by deriving from them.
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Debugging in Clojure? [closed]
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There's also dotrace, which allows you to look at the inputs and outputs of selected functions.
(use 'clojure.contrib.trace)
(defn fib[n] (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))
(dotrace [fib] (fib 3))
produces the output:
TRACE t4425: (f...
Python, creating objects
... = ""
age = 0
major = ""
# The class "constructor" - It's actually an initializer
def __init__(self, name, age, major):
self.name = name
self.age = age
self.major = major
def make_student(name, age, major):
student = Student(name, age, major)
return...
Permutations in JavaScript?
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If you notice, the code actually splits the chars into an array prior to do any permutation, so you simply remove the join and split operation
var permArr = [],
usedChars = [];
function permute(input) {
var i, ch;
for (i = 0; i < inp...
Output to the same line overwriting previous output?
...o need to import the sys module for this sort of simple usage. print() actually has a number of keyword arguments which can be used to greatly simplify code.
To use the same code on Python 2.6+, put the following line at the top of the file:
from __future__ import print_function
...
Remove not alphanumeric characters from string
...e them.
A backslash in the string needs escaping if it's to be taken literally:
"\\test\\red\\bob\\fred\\new".replace(/\W/g, '')
"testredbobfrednew" // output
Handling malformed strings
If you're not able to escape the input string correctly (why not?), or it's coming from some kind of untruste...
Importing modules from parent folder
...t can matter if somewhere else then the parentdir, but in one of the paths allready specified in sys.path, there is another module with the name 'mymodule'. Inserting the parentdir as the first element of the sys.path list assures that the module from parentdir will be imported instead.
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