An algorithm has been written in pseudocode to input 100 numbers, select and print the largest number and smallest number. ``` Count ← 1 INPUT Number High ← Number Low ← Count REPEAT INPUT Number IF Number > High THEN High ← Number ENDIF IF Number > Low THEN Low ← Number ENDIF Count ← Count + 1 UNTIL Count = 99 PRINT "Largest Number is ", Number PRINT "Smallest Number is ", Low ``` Find the four errors in the pseudocode and suggest a correction for each error.

Mark scheme

Marking points from the official mark scheme (May/June 2019). The mark or mark type is shown in brackets.

1. [4] Low ← Count should be Low ← Number
2. [4] Number > Low should be Number < Low
3. [4] UNTIL Count = 99 should be UNTIL Count > 99 or UNTIL Count = 100 or UNTIL Count >= 100 // Count ← 1 should be Count ← 0
4. [4] PRINT "Largest Number is ", Number should be PRINT "Largest Number is ", High
5. [4] MP1 Add Total ← 0 // Total ← Number
6. [4] MP2 Add Total ← Total + Number
7. [4] MP3 Add PRINT "Total is ", Total
8. [4] MP4 All positioning explained / seen
9. [4] (Sample code:) Count ← 1 INPUT Number High ← Number Low ← Number Total ← Number REPEAT INPUT Number Total ← Total + Number IF Number > High THEN High ← Number ENDIF IF Number < Low THEN Low ← Number ENDIF Count ← Count + 1 UNTIL Count > 99 PRINT "Largest Number is ", High PRINT "Smallest Number is ", Low PRINT "Total is ", Total