problem with input and output on C++ programming.
 

As i am new to C++ i couldn't figure out how to input a file and make some change on the file and produce a output file. like this problem i have is.

"Program that processes an input file and produces an output file. The input file will contain lines of data, each containing two floating point numbers. The lines of the output file should contain the two numbers read and their average (with a '$' sign and 2 places after the decimal point)."

Thank you for your help in advance.

you can find here
http://www.cppreference.com/wiki/io/start
all infos that you need for your homework

thankc for the link.