int jerseyNumber = Console.ReadLine();

1-8-registration.cs(2,20): error CS0029: Cannot implicitly convert type 'string' to 'int'
The build failed. Fix the build errors and run again.

int jerseyNumber = int.Parse(Console.ReadLine());

Jersey number: 24 [Enter]
Next season you could be 25.

int.Parse(Console.ReadLine())

double average = double.Parse(Console.ReadLine());

Average points per game: 18.4 [Enter]
Scoring 18.4 a game

double average = 18.4;
double threeGames = average * 3;

Console.WriteLine($"Three games: {threeGames}");

Three games: 55.199999999999996

Three games: 55.199999999999996

Console.WriteLine($"Three games: {threeGames:F2}");

Three games: 55.20

Console.WriteLine($"Scoring: {average} a game");
Console.WriteLine($"Scoring: {average:F2} a game");

Scoring: 18.4 a game
Scoring: 18.40 a game

Console.WriteLine($"Rounded: {threeGames:F2}");
Console.WriteLine($"Raw:     {threeGames}");

Rounded: 55.20
Raw:     55.199999999999996

int players = int.Parse(Console.ReadLine());

How many players signed up? seven [Enter]
Unhandled exception. System.FormatException: The input string 'seven' was not in a correct format.
   at System.Number.ThrowFormatException[TChar](ReadOnlySpan`1 value)
   at System.Int32.Parse(String s)
   at Program.<Main>$(String[] args) in 1-9-planner.cs:line 2

'F' → Fullscreen

Build

Open your 1-8-registration program for Task 1. Everything after that goes in a new program named 1-9-planner.

Task 1: Finish Last Session

• Uncomment the two lines you left broken at the end of Activity 1.8.
• Add int.Parse around the Console.ReadLine call and run it.
• Compare it with the guess you wrote down. Being wrong costs nothing; not having guessed costs the session.

1
Console.Write("Jersey number: ");
2
int jerseyNumber = int.Parse(Console.ReadLine());
3

4
Console.WriteLine($"Next season you could be {jerseyNumber + 1}.");

Jersey number: 24 [Enter]
Next season you could be 25.

Task 2: The Tournament Planner

• Start 1-9-planner empty. Ask for the number of players and the team size, then work out the teams.
• This is Activity 1.6's tournament with the numbers taken out. Run it with 47 and 6 first and check you still get 7 and 5.
• Then run it again with numbers of your own choosing.

1
Console.Write("How many players signed up? ");
2
int players = int.Parse(Console.ReadLine());
3

4
Console.Write("How many to a team? ");
5
int perTeam = int.Parse(Console.ReadLine());
6

7
int fullTeams = players / perTeam;
8
int leftOver = players % perTeam;
9

10
Console.WriteLine();
11
Console.WriteLine("=== TOURNAMENT PLAN ===");
12
Console.WriteLine($"Players:    {players}");
13
Console.WriteLine($"Full teams: {fullTeams}");
14
Console.WriteLine($"Left over:  {leftOver}");

How many players signed up? 47 [Enter]
How many to a team? 6 [Enter]

=== TOURNAMENT PLAN ===
Players:    47
Full teams: 7
Left over:  5

Task 3: Two More Questions, and Making Them Readable

• Ask for an entry fee per team and compute the total cost.
• Ask for an average points-per-game, which is not a whole number. Use double.Parse for that one.
• Work out what a team would score across three games, and print that too.
• Run it with no :F2 anywhere first. Type 18.4 for the average. Write down exactly what the three-game number looks like — all of it.
• Then add :F2 to the average and the projection, and run it again. Write down what each one says now.
• Note: the green lines marked with a + sign are new. Do not type the + sign.

1
Console.Write("How many players signed up? ");
2
int players = int.Parse(Console.ReadLine());
3

4
Console.Write("How many to a team? ");
5
int perTeam = int.Parse(Console.ReadLine());
6

7
Console.Write("Entry fee per team? ");
8
int teamFee = int.Parse(Console.ReadLine());
9

10
Console.Write("Average points per game? ");
11
double average = double.Parse(Console.ReadLine());
12

13
int fullTeams = players / perTeam;
14
int leftOver = players % perTeam;
15
double threeGames = average * 3;
16

17
Console.WriteLine();
18
Console.WriteLine("=== TOURNAMENT PLAN ===");
19
Console.WriteLine($"Players:    {players}");
20
Console.WriteLine($"Full teams: {fullTeams}");
21
Console.WriteLine($"Left over:  {leftOver}");
22
Console.WriteLine($"Entry cost: {fullTeams * teamFee}");
23
Console.WriteLine($"Scoring:    {average:F2} a game");
24
Console.WriteLine($"Three games: {threeGames:F2}");

Task 4: Break It on Purpose

Five runs of your finished planner. Write down exactly what happens each time, copied from the screen.

1. For the number of players, type seven instead of 7.
2. For the number of players, press Enter without typing anything.
3. For the number of players, type 3.5.
4. For the number of players, type 47 with a space before and after it.
5. For the average points, type 3.5.

Three of these stop the program and two do not. For each one that stops, write down the line number it names.

Challenge (Optional): Where Would You Put the Check?

• You cannot fix Task 4 yet. Deciding what to do about bad input needs an if, and that is session 12.
• Write a comment saying where in your program a check would have to go, and what it would have to ask.
• Describing it in plain English is the exercise. No code.

Checkpoint

Your finished planner should run like this.

How many players signed up? 47 [Enter]
How many to a team? 6 [Enter]
Entry fee per team? 25 [Enter]
Average points per game? 18.4 [Enter]

=== TOURNAMENT PLAN ===
Players:    47
Full teams: 7
Left over:  5
Entry cost: 175
Scoring:    18.40 a game
Three games: 55.20

• Every number in the summary came from an answer, not from your code.
• 47 and 6 still produce 7 and 5.
• The average uses double.Parse, and the rest use int.Parse.
• Both decimal lines print with exactly two decimal places, and you have the unformatted three-game number written down.
• All five Task 4 results are written down, with line numbers where the program stopped.

Reflection

Answer the following questions before submitting your work.

1. Describe what happens in int.Parse(Console.ReadLine()), in the order it happens. Name what each part hands to the next.
2. Activity 1.8's mistake was refused before the program ran. This session's only appears when somebody types the wrong thing. Which is more dangerous, and why?
3. Typing 3.5 for the number of players stopped the program, even though 3.5 is obviously a number. Explain why int.Parse refused it.

Submit

Submit five things to the dropbox:

1. Your 1-9-planner program file.
2. A copy of one full run with 47 players and teams of 6.
3. The three-game number as it printed before you added :F2, and as it printed after.
4. Your five Task 4 results, with the line numbers.
5. Your three reflection answers.

Activity Complete