What does #!/bin/bash set -o pipefail if [[ $# -ne 1 ]] if [ $? -eq 0 ] mean in shell scripting

Question

I am going through one script and found this:

#!/bin/bash
set -o pipefail
if [[ $# -ne 1 ]]
if [ $? -eq 0 ]

Answer 1

$# is "amount" of positional parameters

example:

./script.sh foo bar

here we have 2 positional parameters (foo and bar)

this code checks if positional parameters "count" is not 1