Study the following pseudocode for a recursive function. FUNCTION Unknown(BYVAL X, BYVAL Y : INTEGER) RETURNS INTEGER IF X < Y THEN OUTPUT X + Y RETURN (Unknown (X + 1, Y) * 2) ELSE IF X = Y THEN RETURN 1 ELSE OUTPUT X + Y RETURN (Unknown (X 1, Y) DIV 2) ENDIF ENDIF ENDFUNCTION The operator DIV returns the integer value after division e.g. 13 DIV 2 would give 6

1. (a)Write program code to declare the function Unknown(). Save your program as question 1. Copy and paste the program code into part 1(a) in the evidence document.[3]
2. (b)(i)For each of the three function calls, the main program needs to: • output the value of the two parameters • call the function with those parameters • output the return value. Write the program code for the main program. Save your program. Copy and paste the program code into part 1(b)(i) in the evidence document.[3]
3. (b)(ii)Take a screenshot to show the output from part (b)(i). Copy and paste the screenshot into part 1(b)(ii) in the evidence document.[2]
4. (c)Rewrite the function Unknown() as an iterative function, IterativeUnknown(). Save your program. Copy and paste the program code into part 1(c) in the evidence document.[7]
5. (d)(i)The iterative function needs to be called three times with the same parameters as in part (b). For each of the three function calls, the main program needs to: • output the value of the two parameters • call the iterative function with those parameters • output the return value. Amend the main program to perform these tasks. Save your program. Copy and paste the program code into part 1(d)(i) in the evidence document.[1]
6. (d)(ii)Take one or more screenshots to show the output of both functions for each set of parameters. Copy and paste the screenshot(s) into part 1(d)(ii) in the evidence document.[1]