confused about doing this task

The problem asks for a double that represents the value in Fahrenheit degrees. I solved the problem using the formula: TF = (TC * 9.0/5.0) + 32 because that will return such value. I think the problem tricks you into thinking that you need to use the formula for TC, but it's only there to show you the relationship as a reference so you can figure it out from there.

I understood, thank u

(Along with what Khurram said about returning the correct variable) You are using ints instead of doubles in your equation. The conversion to a double happens after the equation evaluates, thus it drops off anything after the decimal. Make one of the changes below and your code will work properly:

TC=(celsius-32) * (double)5/9;

or

TC=(celsius-32) * 5.0/9.0;

return is used to return any value from a method, here you have declared and initialized a variable TC but are returning a variable TF which is not declared in the method