/in/foo.cc: In function 'int main()':
/in/foo.cc:31:29: warning: operation on 'liv' may be undefined [-Wsequence-point]
             a[liv].pre=a[liv++].now=zer;
                          ~~~^~
/in/foo.cc:91:34: warning: operation on 'j' may be undefined [-Wsequence-point]
             for(j=i;j<liv;a[j]=a[++j]);
                                  ^~~