If you could help I'll be very grateful!

Someone suggested FtoC, but I duno...

How do you <snipped link> with pencil & paper ? If you know that then doing it in C or C++ is trivel.

How do you <snipped link> convert between F and C with pencil & paper ? If you know that then doing it in C or C++ is trivel.

Thanks for answering, but I wanted to know if there are any functions which do it, and how to use them

There are no functions -- you have to write your own. you might check out mathlib and boost, I don't know if they have a function or not. But its just a simple one-liner.

Here's how to do it. As I said its only one simple line of code

Convert Fahrenheit to Celsius
Here's How:
1.Determine the temperature in Fahrenheit
2.Using your calculator, subtract 32
3.Multiply the result times 5
4.Divide that answer by 9
5.Your final answer is the temperature in Celsius