Software Engineering is about the analysis, design, coding, documentation, and testing of software to produce, as the historian Barbara Tuchman said in her classic essay on quality, “… the finest and most admirable result possible.”
One important goal of software design is to produce code that other programmers, including your future self when you revisit your own code, will understand.
But what if you want to design and write code that is hard for other programmers to understand?
If so, there is a place for you, the International Obfuscated C Code Contest. Each year they hold a contest to judge the best C code that is hard, if not impossible, to read and understand, with added points for writing code that stresses the C compilers. Ironically, such work emphasizes the need for clear and understandable source code.
Here is the source code for the 2020 prize winner in the Best Utility category, programmed by Ilya Kurdyukov. He formed a good-looking oval with his source code.
Kurdyukov's program is useful. It creates a hash code from a string entered by the user.
To see how this works, copy and paste the program into the online complier at www.onlinegdb.com, choose C as the language, and run the program listed below.
#include <stdint.h>
#include <stdio.h>
#ifdef _WIN32
#include <io.h>
#include <fcntl.h>
#define main() M();i\
nt main(){setmode(fi\
leno(stdin),O_BINARY\
);return M();}int M()
#endif
int main()
{uint32_t h[20]={0},
i=0,x=~i/15,f=x*x-x,a=f^x,
b=f^x*9,c=~a,d=~b;int64_t z=0,
g=0,l=566548,p=585873,o=882346,e
,m=64336,k,n;for(;d=h[c=h[b=h[a=h[i=
0]+=a,1]+=b,2]+=c,3]+=d,f;){for(n=64
;n==8?h[h[5]=g,4]=g>>32,f=z>=0:n;)h[4+
--n/4]=x=(z<0?0:(z=getchar())>=0?g+=8,z:
128)<<24|x>>8;;for(e=0,k=~e<<40;(x=i/16)
<4;a=d,d=c,c=b,b+=x<<n|x>>(32-n))n=((e*m
+k*p)>>21)+e*l+k*o,k=(((k*m-e*p)>>21)+k*
l-e*o)>>20,e=n>>20,n=(i|12)*152%543%82
%4+i%4*43/8+4,x=a+((x>2?~d|b:x>1?b^d
:x?(b^c)&d:(c^d)&~b)^c)+h[19-((x*7/2
&5)-~(x*5&6)*i++)%16]+(e>>40^e>>
8);}for(;i<33;putchar(i++<32?a
+=a>9?'a'-10:'0':'\n'))a=h
[i/8]>>(i%8*4^4)&15;
return 0;}