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Title: Obfuscated code Post by -D- on Aug 6th, 2002, 11:35am The code isn't so obfuscated when it's written like PROPER code.... #include <stdio.h> #define _ F-->00 || F-OO--; void F_OO(); long F=00,OO=00; void main() { F_OO(); printf("%1.3f\n", 4.0*-F/OO/OO); } void F_OO() { ... } This is pretty much the first 3 lines expanded. The #define is a macro that defines the _ character. But it is only expanded for cases where the _ isn't used in a label (such as it is used in F_OO ). F_OO is actually a function that uses long drawn out operation on F and OO to make them become -202 and -16 respectively. 4 * -202 / -16 / -16 = 3.156 which is what is printed out. The 4. in the given code is really 4.0. the - sign is actually a unary minus making the -202 into 202, it doesn't do a subtraction. It wouldn't have been as obfuscated if it had been written -4.*F/OO/OO see? So, the code calls the F_00 function to change the values of F and OO, then prints out some math mangling of those values. The last thing that makes this code more complicated is that they didn't declare their return types for F_OO or main and attempted to assume then as void (which is invalid, proper C would default them to integers). I'll ignore errors associated with not declaring includes or function prototypes and assume those were just not put in the excerpt. -D- |
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Title: Re: Obfuscated code Post by anton on Dec 25th, 2004, 12:28am Since 4.*-F/OO/OO results in an approximation of Pi, we get: Pi = -4F/OO2 Pi*(OO/2)2 = -F It makes sense to assume that OO is the diameter of a circle, and F is its area (negative). The circle is actually the one "drawn" in the function F_OO(). Later, I will replace F with a and OO with d. Let's see what happens in the F_OO function. Each line consists of "_" followed by a string of "-_". Each "_" is replaced with "a-->0 || a-d--;" which means following:
The underscore in each "-_" is replaced with the same thing; the only difference is the initial minus sign. Now -a is compared with zero; since -a is always positive, the second part never gets executed. And now we get the full picture: each of "_" and "-_" decreases a by one; thus, a contains the negative area of the circle. In addition, each initial "_" decreases d by one - in the end d becomes equal to the negative height of the circle, which is the same as its diameter. |
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Title: Re: Obfuscated code Post by Paul on Apr 6th, 2013, 10:07pm People keep showing fractions of pi.You all need to realise pi is a whole number and the rest of the numbers are the fractions.Point then nonpoint.The nonpoint should be a whole number?Ok,seems right doesn't it? |
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