[C++] Interesting example of C++ code obfuscation
Recently a friend of mine has given me a piece of code in C++: puts(&3["abcdef"]);puts(&3["abcdef"]); At first glance it seems to not compile at all. But not only it compiles, but also prints “def”.
[Python,Algorithms] Fast Modular exponentiation script
If we want to know the last ten digits of number an – we have to evaluate expression an mod 1010. Using brute force approach, we have to do O(n) ( If you don’t understand big „O” notation, visit: Big O notation – it’s VERY important) multiplications and modulo divisions. When n is greater than 109, it will take a lot of time. Fortunately, we can use more „mathematical” approach, which has O(log n) complexity.
[PHP] Execution/evaluation of code from variable
In PHP we can use function eval in order to evaluate given variable (string) as PHP code: <? $var = ‘for ($i=0;$i<5;$i++) { echo $i.\'<br>\’; }’; eval($var); ?><? $var = ‘for ($i=0;$i<5;$i++) { echo $i.\'<br>\’; }’; eval($var); ?> output: 0 1 2 3 40 1 2 3 4