I am learning the C++ program and need make a program which shows a simple graph with characters or more complicated bar graph. But I have no resource to learn it,somebody can give me a example about them? Thank you very much!

how to do that depends on the operating system. You can either use operating system-specific GUI drawing functions, or some SDK such as QT that is mostly os-independent. Either way, it will take several months to learn. There are some commercial graph packages you can buy -- some may even be free open source. You will have to google for them.