First argument is hostname and second is password.

     #!/usr/bin/expect
     set pass [lindex $argv 1]
     set host [lindex $argv 0]
     spawn ssh -t root@$host echo Hello
     expect "*assword: "
     send "$pass\n";
     interact

Execution: ./script.expect

First argument is hostname and second is password.

     #!/usr/bin/expect
     set pass [lindex $argv 1]
     set host [lindex $argv 0]
     spawn ssh -t root@$host echo Hello
     expect "*assword: "
     send "$pass\n";
     interact

Execution:

./script.expect hostname "my!password?"