Answer:
Its outfile<<number.
However, before this we need to write
outfile.open("xyz.txt", ios;;out)
outfile<<number
And this code will do what is required in the question. This is going to write the number's content to the xyz.txt file which is the file associated with the outfile.
And remember this is in C++. And C++ is a imperative oriented programming language. Undoubtedly, Python and R are fully object oriented programming languages.
Step-by-step explanation:
The answer is self explanatory.