Your 1st question:
In picture one - Line 12 - int main(), there is a green squiggly line under the word main
This is because at the end of the function you are not returning any value.
So to avoid that,write return 0
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Your 2nd question:
picture 2 - My output is not generated. I showed how when you input the number of elements for arrays and click enter the numbers do not appear, then I clicked enter more times for you to see nothing happened when I clicked enter until I input numbers myself.
You are getting this because in the code any message like "Enter numbers" is not written. Without any message user is expected to enter numbers. So that's why after entering number of elements for array let n, immediately the user is expected to enter n number one after another.
If you want any message to let user know when to enter numbers, just display a message asking user to enter numbers.
For that reason, I have added a message asking user to enter numbers.