/in/foo.cc: In function 'int main()':
/in/foo.cc:9:29: warning: statement has no effect [-Wunused-value]
                        for(a;a<=n-1;a++)
                             ^
/in/foo.cc:14:28: warning: unused variable 'a' [-Wunused-variable]
                        int a=1;
                            ^
/in/foo.cc:33:28: warning: unused variable 'a' [-Wunused-variable]
                        int a=1;
                            ^