Sort Names by Surname

2026/Feb/Mar·Variant 2·Q5·[8 marks]

MEDIUM2D Arrays

Four people are stored in a 2D array Names[1:4, 1:2]: column 1 is the last name, column 2 is the first name. Read the four pairs (last name then first name), bubble-sort the rows into ascending last-name order, and output each person as Last First.

Equal last names should keep their original order.

Input: Eight strings — last name, first name, four times. Output: Four lines after sorting.

Example:

Input:  Chen
        Amy
        Patel
        Bo
        Adams
        Cy
        Chen
        Dan
Output: Adams Cy
        Chen Amy
        Chen Dan
        Patel Bo

Sample Test Cases

Test 1: Two Chens keep input order

Inputs: Chen, Amy, Patel, Bo, Adams, Cy, Chen, Dan

Expected: Adams Cy Chen Amy Chen Dan Patel Bo

Test 2: Reverse alphabetical last names

Inputs: Zed, A, Yap, B, Xu, C, Wu, D

Expected: Wu D Xu C Yap B Zed A