For competitions here is utility competition_init
It can initialize new solution file based on small template file. Just write:

$ ./competition_init <task_name>

This produces file named <task_name>.cpp and empty file for input data: <task_name>.in
One can embed input data under "Input:" section in comments and later restore input file
with exactly the same command as for initialization if there is no <task_name>.in yet.
So you can't accidentlly overwrite <task_name> files in a rush with this utility.

$ ./competition_init <task_name>
Input data for <task_name> restored

Run the solution with command:

$ ./<task_name>.o < <task_name>.in

or configure launch.json in VS Code with settings:

"program": "${workspaceFolder}/<task_name>.exe",
"args": ["<", "${workspaceFolder}/<task_name>.in"],

or, if you got expected output listing, run this way:

$ time (./<task_name> < <task_name>.in) > my.out && diff my.out expected.out