This app was initially for personal use but is now offered free to anyone. It retrieves the current CAD$/USD$ exchange rate but allows you to override it. It calculates the equivalent USD$ per gallon price from the CAD$ per liter price you input. This gives you a chance to quickly compare Canadian fuel prices in a manner US travelers are used to.
I was a COBOL programmer by profession almost 40 years ago. I am trying some new programming now, so go easy on me!