Programming Test

Section 1 - data comparison.

The data we will be trying to process will all be in the form of strings. The problem is that these are also used to represent numbers, and dates. String comparison with <, =, >, etc. though produces a lexical sort, meaning that, for example, "12" is less than "2", and "28 Aug 1959" is greater than "1 Jan 2025". So we need a function that will see if a string represents a number or a date, and if so, return that value for comparison instead of the string. With that in mind, make the appropriate changes to the function below. Things you need to know: "Number(x)" and "Date.parse(x)" are built-in functions that try to interpret a string as respectively a number and a date (or date/time - the latter returning a number which is the number of milliseconds since midnight on January 1, 1970), both returning "NaN" ("not a number") if they are unable to do so. The function "isNaN(x)" may be used to test for a "NaN" value.

Test function

function valueForComparison(s) { // Check here for strings that represent numbers, or dates return s; }

Section 2 - sorting.

Moroccan National Football Team
October 2025	November 2025
Number Name DOB Position 12 Munir Mohamedi 10 May 1989 Goalkeeper 1 Yassine Bounou 5 Apr 1991 Goalkeeper 18 Jawad El Yamiq 29 Feb 1992 Defender 15 Mohamed Chibi 21 Jan 1993 Defender 20 Ayoub El Kaabi 25 Jun 1993 Forward 6 Adam Masina 2 Jan 1994 Defender 5 Nayef Aguerd 30 Mar 1996 Defender 4 Sofyan Amrabat 21 Aug 1996 Midfield 19 Youssef En-Nesyri 1 Jun 1997 Forward 26 Anas Bach 10 Feb 1998 Midfield 3 Youssef Belammari 20 Sep 1998 Defender 2 Achraf Hakimi 4 Nov 1998 Defender 10 Brahim Díaz 3 Aug 1999 Forward 21 Amine Adli 10 May 2000 Forward 24 Souffian El Karouani 19 Oct 2000 Defender 22 El Mehdi Al Harrar 30 Nov 2000 Goalkeeper 11 Ismael Saibari 28 Jan 2001 Midfield 8 Neil El Aynaoui 2 Jul 2001 Midfield 17 Abde Ezzalzouli 17 Dec 2001 Forward 14 Oussama Targhalline 20 May 2002 Midfield 9 Hamza Igamane 2 Nov 2002 Forward 25 Omar El Hilali 12 Sep 2003 Defender 16 Ilias Akhomach 16 Apr 2004 Forward 23 Bilal El Khannouss 10 May 2004 Midfield 13 Eliesse Ben Seghir 16 Feb 2005 Midfield 7 Chemsdine Talbi 9 May 2005 Forward	Number Name DOB Position 1 Yassine Bounou 5 Apr 1991 Goalkeeper 2 Youssef Belammari 20 Sep 1998 Defender 3 Noussair Mazraoui 14 Nov 1997 Defender 4 Sofyan Amrabat 21 Aug 1996 Midfield 5 Adam Masina 2 Jan 1994 Defender 6 Romain Saïss 26 Mar 1990 Defender 7 Chemsdine Talbi 9 May 2005 Forward 8 Azzedine Ounahi 19 Apr 2000 Midfield 9 Soufiane Rahimi 2 Jun 1996 Forward 10 Brahim Díaz 3 Aug 1999 Forward 11 Ismael Saibari 28 Jan 2001 Midfield 12 Munir Mohamedi 10 May 1989 Goalkeeper 13 Eliesse Ben Seghir 16 Feb 2005 Midfield 14 Oussama Targhalline 20 May 2002 Midfield 15 Mohamed Chibi 21 Jan 1993 Defender 16 Ilias Akhomach 16 Apr 2004 Forward 17 Abde Ezzalzouli 17 Dec 2001 Forward 18 Jawad El Yamiq 29 Feb 1992 Defender 19 Youssef En-Nesyri 1 Jun 1997 Forward 20 Ayoub El Kaabi 25 Jun 1993 Forward 21 Hamza Igamane 2 Nov 2002 Forward 22 Bilal El Khannouss 10 May 2004 Midfield 23 Neil El Aynaoui 2 Jul 2001 Midfield 24 Sofiane Diop 9 Jun 2000 Forward 25 Anass Salah-Eddine 18 Jan 2002 Defender 26 Abdelhamid Aït Boudlal 16 Apr 2006 Defender

Double-clicking the column headers will reverse the order of the list, but what we want is for it to sort the list on that particular column instead.

Just two functions are provided to access the data:

exchRows(tbl, row1, row2)	exchanges row1 and row2
compareRows(tbl, row1, row2, sortCols)	compares row1 and row2, returning -1, 0, or 1 according to whether row1 is less than, equal to, or greater than row2

Numbering of rows is from 1 to n, and you need to sort from smaller to greater. The variable sortCols is a record of the last four columns double clicked, numbering columns from 1 to 4. This should be passed to compareRows without further processing. Double-clicking twice on a column header changes the value to minus the value, which is a signal to reverse the comparison, causing the data to come out in reverse order. Historical column numbers form the secondary, tertiary, etc. keys for the sort.

function sort(tbl, n, sortCols) { for (i = 1; i <= n / 2; i++) exchRows(tbl, i, n + 1 - i) }

Error Label

Section 3 - differencing.

Determine changes in team

The function changesInTeam receives zero-based, sorted arrays of the players’ names from which you need to produce a zero-based array whose elements are, respectively, a comma-separated list of the players dropped, and a comma-separated list of the players added. You can get the number of elements of an array with .length. If the array index exceeds the bounds then the value undefined will be returned rather than an error, and this value can be tested for. Array.push(elem) can be used to simultaneously enlarge the array by one and make the last element equal to <elem>.

function changesInTeam(teamBefore, teamAfter) { playersDropped = []; playersAdded = []; // Populate playersDropped and playersAdded from the differences return [playersDropped.join(", "), playersAdded.join(", ")]; }

Players dropped:

Players added:

Final section - send code snippets / comments.

Well done for getting this far! In my humble opinion, this kind of detailed work, where you have to really think about what you are doing is what programming is all about, and what makes it interesting. Now you can

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