/in/foo.cc: In function 'void print()':
/in/foo.cc:6:7: error: 'sumw' was not declared in this scope
     w=sumw-w;
       ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:34:15: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
             if(f[j+a[i]]>0)
               ^