Quote:
I tried to do it but it never works for me
We know it didn't work for you because otherwise you wouldn't be here.
Show your code and explain your problem, showing actual result is also an information.
[Update]
Try to replace
cout<<num;
with
cout<<lineNo;
You were writing the number of lines instead of the current line number.
[End Update]
We do not do your HomeWork.
HomeWork is not set to test your skills at begging other people to do your work, it is set to make you think and to help your teacher to check your understanding of the courses you have taken and also the problems you have at applying them.
Any failure of you will help your teacher spot your weaknesses and set remedial actions.
So, give it a try, reread your lessons and start working. If you are stuck on a specific problem, show your code and explain this exact problem, we might help.
As programmer,
your job is to create algorithms that solve specific problems and you can't rely on someone else to eternally do it for you, so there is a time where you will have to learn how to. And the sooner, the better.
When you just ask for the solution, it is like trying to learn to drive a car by having someone else training.
Creating an algorithm is basically finding the maths and make necessary adaptation to fit your actual problem.
Advice: take a sheet of paper and try to do it by hand, your program should use the same procedure.