Rotary Encoder w/ LED status bar

How do I make a code that would modify the program which will display a status bar (LED displays to act as status bar) if the frequeny increases the status bar increases and vice versa. The frequency starts with 100.

You need to explain the project in a lot more detail before you can get meaningful help. Some questions that need answering are...
Where is the rotary encoder used in this. Does it count pulses to derive the frequency your looking for?
You say the frequency starts at 100 but 100 what (Hz, KHz, MHz, RPM)
The LED display is a bar graph? And how many LEDs are we talking about?