/in/foo.cc: In function 'int main()':
/in/foo.cc:82:71: error: expected primary-expression before 'if'
     FOR(i,0,n/2)rnk[l]<rnk[r]?printf("%c",s[l++]):printf("%c",s[r++]),if((i+1)%80==0)printf("\n");
                                                                       ^~