can anyone help me with this assignment, Please.

The brightness of a binary star varies as follows. At time t = 0 days its magnitude is 2.5, and it stays at this level until t = 0.9 days. Its magnitude is then determined by the formula

3.355-ln(1.352+cos(PI(t-0.9)/0.7))

Until t = 2.3 days its magnitude is then 2.5 until t = 4.4 days, and it is then determined by the formula

3.598-ln(1.998+cos(PI(t-4.4)/0.4))

Until t = 5.2. It then remains at 2.5 until t = 6.4 days, after which the cycle repeats with a period of 6.4 days.

Write a program which will input the value of t and print the brightness of the star at that time. Use the value of PI = 3.14285714.

Your program should give the user the option to repeat the process of computing the brightness of star or stop (EXIT) the code. Also, you should use nested if , switch control structure statements in your solution. Your results should be displayed in five decimal places.

My main problem is **what will be the condition for the loop** ?

and is it better to use while() or do{} while() ?