How could we write a code in c++ language to change some digits into binary codes?

Answer 1

I guess you want to convert a decimal number into a binary number?

There are two algorithms for that: The "Euclidian algorithm" and the "Horner scheme". Just google them, there are some good explanations.

If you want a solution, take a look at my codes, I implemented both algorithms a while ago. But I advise trying the figure out the solution yourself, you'll learn a lot more from that.