Increase the_excerpt() content length in wordpress

For our customization want to increase the_excerpt() content length then using the excerpt_length filter. by default expert length is 55. for example you want to change length in to 100 then place the following snippet in functions.php within your theme folder!.

function increase_custom_excerpt_length( $length ) {
    return 100;
}
add_filter( 'excerpt_length', 'increase_custom_excerpt_length', 999 );

Have any doubt, then comment here!