/in/foo.c: In function 'main':
/in/foo.c:7:7: warning: statement with no effect [-Wunused-value]
  for(i==1;i<=n;i++)
      ~^~~
/in/foo.c:9:10: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  sum=sum+pow(i,2);
          ^~~~~~~~