Pi

int a=10000,b,c=2800,d,e,f[2801],g;main(){for(;b-c;)f[b++]=a/5;
for(;d=0,g=c*2;c-=14,printf("%.4d",e+d/a),e=d%a)for(b=c;d+=f[b]*a,
f[b]=d%--g,d/=g--,--b;d*=b);}

>>7
None of his loops lack proper conditional statements. l2C.
It's true that he's depending on auto-initialisation to 0, which isn't guaranteed at all. However,

b will be initialized to whatever junk data is stored at the memory location allocated
Memory is cleared by the OS before it is allocated to applications in every OS that does memory protection (and most that don't). I know it's a popular misconception that uninitialised variables will contain whatever happened to be there from the last time an application used that bit of memory, but that's total toss.

Anyway, the main problems are lack of initialisation and a malformed main declaration. Sensible compilers and platforms would reject the code altogether, but it will probably do what he expects it to on most.