This code prints the map of India. How does it work?
Code:#include <stdio.h> main() { int a,b,c; int count = 1; for (b=c=10;a="- FIGURE?, UMKC,XYZHello Folks,\ TFy!QJu ROo TNn(ROo)SLq SLq ULo+\ UHs UJq TNn*RPn/QPbEWS_JSWQAIJO^\ NBELPeHBFHT}TnALVlBLOFAkHFOuFETp\ HCStHAUFAgcEAelclcn^r^r\\tZvYxXy\ T|S~Pn SPm SOn TNn ULo0ULo#ULo-W\ Hq!WFs XDt!" [b+++21]; ) for(; a-- > 64 ; ) putchar ( ++c=='Z' ? c = c/ 9:33^b&1); return 0; }
The "joy" of obfuscated code is that YOU get to work out why it works. The whole point of obfuscated coding contests is to highlight the benefits of good coding practice, by showing how badly things can be done.
That code is making use of a couple of obscure and dark corners of C. You'll need to understand those to understand what the code does, otherwise any description people give you will seem meaningless.
Even worse, there is at least one example of implementation-defined behaviour, so the code is not guaranteed to work with all compilers.
Please can you provide me any link to where i can learn about this dark corners?Originally Posted by grumpy
I assume you know the conditional operator and that the \ at the ends of the lines building the string cause the newline to be ignored.
Remember that characters are also numbers. Look at an ascii table. E.g., 'Z'==90, '!'==33, ' '==32
You need to know operator precedence. 33 ^ b & 1 == 33 ^ (b & 1)
String constants can be indexed like arrays: "abcdefg"[3] == 'd'
(b+++21) == (b++ + 21)
The map is stored in the string by run-length-encoding. Basically, how many spaces, how many bangs, how many spaces, etc. Directing the output to a file is informative. Note the spaces on the right.
Try rewriting the code as clearly as you can.
* Properly indent it.
* Put the string together on one line.
* Remove the conditional operator.
* Change letters to numbers where it makes more sense.
* Simplify anything you can.
* Always run it after each change to make sure you didn't mess something up.
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Last edited by oogabooga; 08-17-2013 at 03:49 PM.
The cost of software maintenance increases with the square of the programmer's creativity. - Robert D. Bliss
