In C language

4. One snail is climbing up the tree. For each round, it climb up a random distance between [Ocm, 10cm). Finish the following problems: Write a function named calculate_dis. This function has one parameter n with int type, and should output the total distance that the snail has climbed in the n rounds. (2 marks) Write a function named rounds_ needed. This function has one parameter D with int type, and should output the total rounds that the snail will take to climb up no less than D cm. (2 marks) Under the assumption that D=100, calculate rounds_ needed (D) for multiple (no less than 100) times (with different starting seeds to generate different random numbers each time). Based on the result, please answer: - What is the average value of rounds_needed(D) in your experiment? (1 mark) What is the relation between D and rounds_needed(D)? Please explain the reason. (1 mark)