How to use an if else statement in a loop in C? [closed]

Write an if else statement that follows the pseudocode: prompt the user to enter a mark (0-100) ask for the mark if the user enters 80-100 print Excellent else if the user enters 65-79 print Very Good else if the user enters 50-64 print Average else if the user enters 40-49 print Poor else print Fail the user can repeat the above steps until a -1 is entered Finally print out the total and average marks entered