*** Answer must be in C language only***

Can you help me write a program for this in C language?

A robot can take steps of 1 meter, 2 meters or 3 meters. Write a recursive function to calculate the number of ways that robot can walk n meters (n is an integer obtained from user). As examples:

Sample Program execution is as follows:

Please enter the distance that the robot will walk: 4

There are 7 ways to walk 4 meters with steps of 1 meter, 2 meters, and 3 meters.

NOTE 1: non-recursive solution is NOT acceptable.