/in/foo.c: In function 'main':
/in/foo.c:5:16: error: expected ';' before ')' token
  for (i = 1;i++);
                ^
/in/foo.c:5:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for (i = 1;i++);
  ^~~
/in/foo.c:6:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  {
  ^
/in/foo.c:4:10: warning: unused variable 'sum' [-Wunused-variable]
  int i,j,sum=0;
          ^~~