Mysql 8 accidentally lost ROOT user all privileges in localhost wampserver 3.2
Thank god,Finally it worked out.
first I created a file named as mysql-init.txt in c drive.The file contains

update mysql.user
set Select_priv='Y',
    Insert_priv='Y',
    Update_priv='Y',
    Delete_priv='Y',
    Create_priv='Y',
    Drop_priv='Y',
    Reload_priv='Y',
    Shutdown_priv='Y',
    Process_priv='Y',
    File_priv='Y',
    Grant_priv='Y',
    References_priv='Y',
    Index_priv='Y',
    Alter_priv='Y',
    Show_db_priv='Y',
    Super_priv='Y',
    Create_tmp_table_priv='Y',
    Lock_tables_priv='Y',
    Execute_priv='Y',
    Repl_slave_priv='Y',
    Repl_client_priv='Y',
    Create_view_priv='Y',
    Show_view_priv='Y',
    Create_routine_priv='Y',
    Alter_routine_priv='Y',
    Create_user_priv='Y',
    Event_priv='Y',
    Trigger_priv='Y' 
where User='root';


Then I run this command.

D:\wamp3\bin\mysql\mysql8.0.18\bin&gt;mysqld --init-file=c:\\mysql-init.txt --conso
le


Then login as root user.Now all database showing up.