/in/foo.cc: In function 'void print()':
/in/foo.cc:6:5: error: 'x' was not declared in this scope
  if(x!=0&&pre[x]!=0)
     ^
/in/foo.cc:7:13: error: 'out' was not declared in this scope
   out(pre[x]);
             ^
/in/foo.cc:8:8: error: 'now' was not declared in this scope
  cout<<now[x]<<' ';
        ^~~
/in/foo.cc:8:12: error: 'x' was not declared in this scope
  cout<<now[x]<<' ';
            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:21:9: error: 'itn' was not declared in this scope
     for(itn i=1;i<=n;i++)
         ^~~
/in/foo.cc:21:17: error: 'i' was not declared in this scope
     for(itn i=1;i<=n;i++)
                 ^
/in/foo.cc:25:10: error: two consecutive '[' shall only introduce an attribute before '[' token
         f[[j]+a[i]=f[j];
          ^
/in/foo.cc:27:9: error: 'now' was not declared in this scope
         now[j+a[i]]=i;
         ^~~
/in/foo.cc:23:9: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
       if(f[j]>0)
         ^