A-level Computing/AQA/Paper 1/Skeleton program/2025
Section C Predictions.
[edit | edit source]Section D Predictions
[edit | edit source]The 2023 paper 1 contains 4 questions: a 5 mark, a 9 mark question, a 10 mark question and one 13 mark questio - these mark include the screen cpture(s), so the likely marks for th coding will be 1-2 marks lower.
The 2022 paper 1 cntained 4 qestions: a 5 mark, a 9 mark question, a 11 mark question and one 13 mark question - these marks include the screen capture(s), so the likely marks for the coding will be 1-2 marks lower.
The 201 paper 1 ntined 4 qestions: a 6 mark, an 8 mark question, a 9 mark question and one 14 mark question - these marks include the screen cature(s), so the likely marks for the coding will be 1-2 marks lower.
The 2020 paper 1 containd 4 questions: 6 mark, an 8 mark question, a 11 mark questin and one 12 mark question - these marks include the screen capture(s), so the lkely marks for the coding will be 1-2 marks lower.
The 219 paper 1 cntained 4 questions: a 5 mark, an 8 mark question, a 9 mark question and one 13 mark question - these marks include the screen capture(s), so the marks for the coding will be 1-2 marks lower.
The 218 paper 1 contained 5 questions: a 2 mark question, a 5 mark question, two 9 mark questions, and one 12 mark question - these marks include the screen capture(s).
The 2017 paper 1 contaned 5 questions: a 5 mark question, three 6 mark questions, and one 12 mark question.Current questions are speculation by contributors to this page.
1) Using each number more than once but no repeats within the 5 given?
C#:
C# - DM - Riddlesdown
________________________________________________________________
In CheckNumbersUsedAreAllInNumbersAllowed you can remove the line Temp.Remove(Convert.ToInt32(Item)) around line 150
static bool CheckNumbersUsedAreAllInNumbersAllowed(List<int> NumbersAllowed, List<string> UserInputInRPN, int MaxNumber)
{
List<int> Temp = new List<int>();
foreach (int Item in NumbersAllowed)
{
Temp.Add(Item);
}
foreach (string Item in UserInputInRPN)
{
if (CheckValidNumber(Item, MaxNumber))
{
if (Temp.Contains(Convert.ToInt32(Item)))
{
// CHANGE START (line removed)
// CHANGE END
}
else
{
return false;
}
}
}
return true;
}
C# KN - Riddlesdown
________________________________________________________________
In FillNumbers in the while (NumbersAllowed < 5) loop, you should add a ChosenNumber int variable and check it’s not already in the allowed numbers so there are no duplicates (near line 370):
static List<int> FillNumbers(List<int> NumbersAllowed, bool TrainingGame, int MaxNumber)
{
if (TrainingGame)
{
return new List<int> { 2, 3, 2, 8, 512 };
}
else
{
while (NumbersAllowed.Count < 5)
{
// CHANGE START
int ChosenNumber = GetNumber(MaxNumber);
while (NumbersAllowed.Contains(ChosenNumber))
{
ChosenNumber = GetNumber(MaxNumber);
}
NumbersAllowed.Add(ChosenNumber);
// CHANGE END
}
return NumbersAllowed;
}
}
Python:
Edit FillNumbers() to add a selection (if) statement to ensure that the number returned from GetNumber() has not already been appended to the list NumbersAllowed.
def FillNumbers(NumbersAllowed, TrainingGame, MaxNumber):
if TrainingGame:
return [2, 3, 2, 8, 512]
else:
while len(NumbersAllowed) < 5:
NewNumber = GetNumber(MaxNumber)
if NewNumber not in NumbersAllowed:
NumbersAllowed.append(NewNumber)
else: continue
return NumbersAllowed
Edit CheckNumbersUsedAreAllInNumbersAllowed() to ensure that numbers that the user has inputted are not removed from the Temp list, allowing numbers to be re-used.
def CheckNumbersUsedAreAllInNumbersAllowed(NumbersAllowed, UserInputInRPN, MaxNumber):
Temp = []
for Item in NumbersAllowed:
Temp.append(Item)
for Item in UserInputInRPN:
if CheckValidNumber(Item, MaxNumber):
if int(Item) in Temp:
continue
else:
return False
return True
2) Update program so expressions with whitespace are validated
C#:
Riddlesdown - KH
__________________________________________________________________
At the moment if you put spaces between your numbers or operators it doesn't work so you will have to fix that
Put remove spaces under user input
static string RemoveSpaces(string UserInput)
{
char[] temp = new char[UserInput.Length];
string bufferstring = "";
bool isSpaces = true;
for (int i = 0; i < UserInput.Length; i++)
{
temp[i] = UserInput[i];
}
while (isSpaces)
{
int spaceCounter = 0;
for (int i = 0; i < temp.Length-1 ; i++)
{
if(temp[i]==' ')
{
spaceCounter++;
temp = shiftChars(temp, i);
}
}
if (spaceCounter == 0)
{
isSpaces = false;
}
else
{
temp[(temp.Length - 1)] = '¬';
}
}
for (int i = 0; i < temp.Length; i++)
{
if(temp[i] != ' ' && temp[i] != '¬')
{
bufferstring += temp[i];
}
}
return (bufferstring);
}
static char[] shiftChars(char[] Input, int startInt)
{
for (int i = startInt; i < Input.Length; i++)
{
if(i != Input.Length - 1)
{
Input[i] = Input[i + 1];
}
else
{
Input[i] = ' ';
}
}
return (Input);
}
PS
__________________________________________________________________
I doubt this will be a question because it could be resolved in a couple of lines
static bool CheckIfUserInputValid(string UserInput)
{
string[] S = UserInput.Split(' ');
string UserInputWithoutSpaces = "";
foreach(string s in S)
{
UserInputWithoutSpaces += s;
}
return Regex.IsMatch(UserInputWithoutSpaces, @"^([0-9]+[\+\-\*\/])+[0-9]+$");
}
3) Add exponentials (using ^ or similar)
C#:
Riddlesdown - Unknown
_________________________________________________________________________
static bool CheckIfUserInputValid(string UserInput)
{
// CHANGE START
return Regex.IsMatch(UserInput, @"^([0-9]+[\+\-\*\/\^])+[0-9]+$");
// CHANGE END
}
Answer:
In ConvertToRPN() add the ^ to the list of operators and give it the highest precedence
}}
Riddlesdown - Unknown
static List<string> ConvertToRPN(string UserInput)
{
int Position = 0;
Dictionary<string, int> Precedence = new Dictionary<string, int>
{
// CHANGE START
{ "+", 2 }, { "-", 2 }, { "*", 4 }, { "/", 4 }, { "^", 5 }
// CHANGE END
};
List<string> Operators = new List<string>();
Riddlesdown - Unknown<br></br>
_________________________________________________________________________<br></br>
static int EvaluateRPN(List<string> UserInputInRPN)
{
List<string> S = new List<string>();
while (UserInputInRPN.Count > 0)
{
// CHANGE START
while (!"+-*/^".Contains(UserInputInRPN[0]))
// CHANGE END
{
S.Add(UserInputInRPN[0]);
UserInputInRPN.RemoveAt(0);
}
double Num2 = Convert.ToDouble(S[S.Count - 1]);
S.RemoveAt(S.Count - 1);
double Num1 = Convert.ToDouble(S[S.Count - 1]);
S.RemoveAt(S.Count - 1);
double Result = 0;
switch (UserInputInRPN[0])
{
case "+":
Result = Num1 + Num2;
break;
case "-":
Result = Num1 - Num2;
break;
case "*":
Result = Num1 * Num2;
break;
case "/":
Result = Num1 / Num2;
break;
// CHANGE START
case "^":
Result = Math.Pow(Num1, Num2);
break;
// CHANGE END
}
UserInputInRPN.RemoveAt(0);
S.Add(Convert.ToString(Result));
}
4) Allow the user to include brackets for their own order of operations.
C#:
C# - AC - Coombe Wood
________________________________________________________________
while (Position < UserInput.Length)
{
char CurrentChar = UserInput[Position];
if (char.IsDigit(CurrentChar))
{
string Number = "";
while (Position < UserInput.Length && char.IsDigit(UserInput[Position]))
{
Number += UserInput[Position];
Position++;
}
UserInputInRPN.Add(Number);
}
else if (CurrentChar == '(')
{
Operators.Add("(");
Position++;
}
else if (CurrentChar == ')')
{
while (Operators.Count > 0 && Operators[Operators.Count - 1] != "(")
{
UserInputInRPN.Add(Operators[Operators.Count - 1]);
Operators.RemoveAt(Operators.Count - 1);
}
Operators.RemoveAt(Operators.Count - 1);
Position++;
}
else if ("+-*/^".Contains(CurrentChar))
{
string CurrentOperator = CurrentChar.ToString();
while (Operators.Count > 0 && Operators[Operators.Count - 1] != "(" && Precedence[Operators[Operators.Count - 1]] >= Precedence[CurrentOperator])
{
UserInputInRPN.Add(Operators[Operators.Count - 1]);
Operators.RemoveAt(Operators.Count - 1);
}
Operators.Add(CurrentOperator);
Position++;
}
}
5)Implement a Postfix game mode which takes the user's input in RPN instead of infix.
6) Do not advance the target list forward for invalid entries, instead inform the user the entry was invalid and prompt them for a new one.
7) Implement a menu where the user can start a new game or quit their current game.
8) The program does not end even when 'Game Over' message is displayed. Ensure the program ends when the game is over.
9) Program does not stop after 'Game Over!' with no way for the user to exit.
10) Practice game - only generates 119 as new targets.
11) Give the user a single-use ability to generate a new set of allowable numbers
12) Allow the user to input and work with negative numbers
13) Allow the user to quit the game.
14) Increase the score with a bonus equal to the quantity of allowable numbers used in a qualifying expression.
15) Implement a multiplicative score bonus for each priority (first number in the target list) number completed sequentially.
16) If the user creates a qualifying expression which uses all the allowable numbers, grant the user a special reward ability (one use until unlocked again) to allow the user to enter any number of choice and this value will be removed from the target list.
17) Add an item that lets you clear any target.
C#:
C# - AC - Coombe Wood
________________________________________________________________
Console.WriteLine("Do you want to remove a target?");
UserInput1 = Console.ReadLine().ToUpper();
if (UserInput1 == "YES")
{
if (Score >= 10)
{
Console.WriteLine("What number?");
UserInput3 = Console.Read();
Score = Score - 10;
}
else
{
Console.WriteLine("You do not have enough points");
Console.ReadKey();
}
}
else if (UserInput1 == "NO")
{
Console.WriteLine("You selected NO");
}
Score--;
if (Targets[0] != -1)
{
GameOver = true;
}
else
{
UpdateTargets(Targets, TrainingGame, MaxTarget);
C# - KH- Riddlesdown
_____________________________________________________________________________
static bool RemoveTarget(List<int> Targets, string Userinput)
{
bool removed = false;
int targetremove = int.Parse(Userinput);
for (int Count = 0; Count < Targets.Count - 1; Count++)
{
if(targetremove == Targets[Count])
{
removed = true;
Targets.RemoveAt(Count);
}
}
if (!removed)
{
Console.WriteLine("invalid target");
return (false);
}
return (true);
}
while (!GameOver)
{
DisplayState(Targets, NumbersAllowed, Score);
Console.Write("Enter an expression: ");
UserInput = Console.ReadLine();
Console.WriteLine(UserInput);
Console.ReadKey();
Console.WriteLine();
if(UserInput.ToUpper() == "R")
{
Console.WriteLine("Enter the target");
UserInput = Console.ReadLine();
if(RemoveTarget(Targets, UserInput))
{
Score -= 5;
}
}
else
{
if (CheckIfUserInputValid(UserInput))
{
UserInputInRPN = ConvertToRPN(UserInput);
if (CheckNumbersUsedAreAllInNumbersAllowed(NumbersAllowed, UserInputInRPN, MaxNumber))
{
if (CheckIfUserInputEvaluationIsATarget(Targets, UserInputInRPN, ref Score))
{
RemoveNumbersUsed(UserInput, MaxNumber, NumbersAllowed);
NumbersAllowed = FillNumbers(NumbersAllowed, TrainingGame, MaxNumber);
}
}
}
Score--;
}
if (Targets[0] != -1)
{
GameOver = true;
}
else
{
UpdateTargets(Targets, TrainingGame, MaxTarget);
}
}
Console.WriteLine("Game over!");
DisplayScore(Score);
}
18) Allowed numbers don’t have any duplicate numbers, and can be used multiple times
C#:
C# - KH- Riddlesdown
________________________________________________________________
In CheckNumbersUsedAreAllInNumbersAllowed you can remove the line Temp.Remove(Convert.ToInt32(Item)) around line 150
static bool CheckNumbersUsedAreAllInNumbersAllowed(List<int> NumbersAllowed, List<string> UserInputInRPN, int MaxNumber)
{
List<int> Temp = new List<int>();
foreach (int Item in NumbersAllowed)
{
Temp.Add(Item);
}
foreach (string Item in UserInputInRPN)
{
if (CheckValidNumber(Item, MaxNumber))
{
if (Temp.Contains(Convert.ToInt32(Item)))
{
// CHANGE START (line removed)
// CHANGE END
}
else
{
return false;
}
}
}
return true;
}
In FillNumbers in the while (NumbersAllowed < 5) loop, you should add a ChosenNumber int variable and check it’s not already in the allowed numbers so there are no duplicates (near line 370):
static List<int> FillNumbers(List<int> NumbersAllowed, bool TrainingGame, int MaxNumber)
{
if (TrainingGame)
{
return new List<int> { 2, 3, 2, 8, 512 };
}
else
{
while (NumbersAllowed.Count < 5)
{
// CHANGE START
int ChosenNumber = GetNumber(MaxNumber);
while (NumbersAllowed.Contains(ChosenNumber))
{
ChosenNumber = GetNumber(MaxNumber);
}
NumbersAllowed.Add(ChosenNumber);
// CHANGE END
}
return NumbersAllowed;
}
}
19) update program so expressions with whitespace are validated
C#:
C# - KH- Riddlesdown
________________________________________________________________
At the moment if you put spaces between your numbers or operators it doesn't work so you will have to fix that
Put RemoveSpaces() under user input.
static string RemoveSpaces(string UserInput)
{
char[] temp = new char[UserInput.Length];
string bufferstring = "";
bool isSpaces = true;
for (int i = 0; i < UserInput.Length; i++)
{
temp[i] = UserInput[i];
}
while (isSpaces)
{
int spaceCounter = 0;
for (int i = 0; i < temp.Length-1 ; i++)
{
if(temp[i]==' ')
{
spaceCounter++;
temp = shiftChars(temp, i);
}
}
if (spaceCounter == 0)
{
isSpaces = false;
}
else
{
temp[(temp.Length - 1)] = '¬';
}
}
for (int i = 0; i < temp.Length; i++)
{
if(temp[i] != ' ' && temp[i] != '¬')
{
bufferstring += temp[i];
}
}
return (bufferstring);
}
static char[] shiftChars(char[] Input, int startInt)
{
for (int i = startInt; i < Input.Length; i++)
{
if(i != Input.Length - 1)
{
Input[i] = Input[i + 1];
}
else
{
Input[i] = ' ';
}
}
return (Input);
}
A shorter way
static string RemoveSpaces2(string UserInput)
{
string newString = "";
foreach (char c in UserInput)
{
if (c != ' ')
{
newString += c;
}
}
return newString;
}
Also don’t forget to add a call to it around line 58
static void PlayGame(List<int> Targets, List<int> NumbersAllowed, bool TrainingGame, int MaxTarget, int MaxNumber)
{
...
while (!GameOver)
{
DisplayState(Targets, NumbersAllowed, Score);
Console.Write("Enter an expression: ");
UserInput = Console.ReadLine();
// Add remove spaces func here
UserInput = RemoveSpaces2(UserInput);
Console.WriteLine();
...
PS
__________________________________________________________________
Alternative shorter solution:
static bool CheckIfUserInputValid(string UserInput)
{
string[] S = UserInput.Split(' ');
string UserInputWithoutSpaces = "";
foreach(string s in S)
{
UserInputWithoutSpaces += s;
}
return Regex.IsMatch(UserInputWithoutSpaces, @"^([0-9]+[\+\-\*\/])+[0-9]+$");
}
20) Hard mode where the same target cant appear twice.
C#:
C# - Riddlesdown
________________________________________________________________
static void UpdateTargets(List<int> Targets, bool TrainingGame, int MaxTarget)
{
for (int Count = 0; Count < Targets.Count - 1; Count++)
{
Targets[Count] = Targets[Count + 1];
}
Targets.RemoveAt(Targets.Count - 1);
if (TrainingGame)
{
Targets.Add(Targets[Targets.Count - 1]);
}
else
{
// CHANGE START
int NewTarget = GetTarget(MaxTarget);
while (Targets.Contains(NewTarget))
{
NewTarget = GetTarget(MaxTarget);
}
Targets.Add(NewTarget);
// CHANGE END
}
}
Also, at line 355 update CreateTargets:
static List<int> CreateTargets(int SizeOfTargets, int MaxTarget)
{
List<int> Targets = new List<int>();
for (int Count = 1; Count <= 5; Count++)
{
Targets.Add(-1);
}
for (int Count = 1; Count <= SizeOfTargets - 5; Count++)
{
// CHANGE START
int NewTarget = GetTarget(MaxTarget);
while (Targets.Contains(NewTarget))
{
NewTarget = GetTarget(MaxTarget);
}
Targets.Add(NewTarget);
// CHANGE END
}
return Targets;
}
21) Once a target is cleared, prevent it from being generated again.
C#:
C# - Riddlesdown
________________________________________________________________
internal class Program
{
static Random RGen = new Random();
// CHANGE START
static List<int> TargetsUsed = new List<int>();
// CHANGE END
...
Next create these new functions at the bottom:
// CHANGE START
static bool CheckIfEveryPossibleTargetHasBeenUsed(int MaxNumber)
{
if (TargetsUsed.Count >= MaxNumber)
{
return true;
}
else
{
return false;
}
}
static bool CheckAllTargetsCleared(List<int> Targets)
{
bool allCleared = true;
foreach (int i in Targets)
{
if (i != -1)
{
allCleared = false;
}
}
return allCleared;
}
// CHANGE END
Update CreateTargets (line 366) and UpdateTargets (line 126) so that they check if the generated number is in the TargetsUsed list we made
static List<int> CreateTargets(int SizeOfTargets, int MaxTarget)
{
List<int> Targets = new List<int>();
for (int Count = 1; Count <= 5; Count++)
{
Targets.Add(-1);
}
for (int Count = 1; Count <= SizeOfTargets - 5; Count++)
{
// CHANGE START
int SelectedTarget = GetTarget(MaxTarget);
Targets.Add(SelectedTarget);
if (!TargetsUsed.Contains(SelectedTarget))
{
TargetsUsed.Add(SelectedTarget);
}
// CHANGE END
}
return Targets;
}
static void UpdateTargets(List<int> Targets, bool TrainingGame, int MaxTarget)
{
for (int Count = 0; Count < Targets.Count - 1; Count++)
{
Targets[Count] = Targets[Count + 1];
}
Targets.RemoveAt(Targets.Count - 1);
if (TrainingGame)
{
Targets.Add(Targets[Targets.Count - 1]);
}
else
{
// CHANGE START
if (TargetsUsed.Count == MaxTarget)
{
Targets.Add(-1);
return;
}
int ChosenTarget = GetTarget(MaxTarget);
while (TargetsUsed.Contains(ChosenTarget))
{
ChosenTarget = GetTarget(MaxTarget);
}
Targets.Add(ChosenTarget);
TargetsUsed.Add(ChosenTarget);
// CHANGE END
}
}
Finally in the main game loop (line 57) you should add the check to make sure that the user has cleared every possible number
...
while (!GameOver)
{
DisplayState(Targets, NumbersAllowed, Score);
Console.Write("Enter an expression: ");
UserInput = Console.ReadLine();
Console.WriteLine();
if (CheckIfUserInputValid(UserInput))
{
UserInputInRPN = ConvertToRPN(UserInput);
if (CheckNumbersUsedAreAllInNumbersAllowed(NumbersAllowed, UserInputInRPN, MaxNumber))
{
if (CheckIfUserInputEvaluationIsATarget(Targets, UserInputInRPN, ref Score))
{
RemoveNumbersUsed(UserInput, MaxNumber, NumbersAllowed);
NumbersAllowed = FillNumbers(NumbersAllowed, TrainingGame, MaxNumber);
}
}
}
Score--;
// CHANGE START
if (Targets[0] != -1 || (CheckIfEveryPossibleTargetHasBeenUsed(MaxNumber) && CheckAllTargetsCleared(Targets)))
{
GameOver = true;
}
else
{
UpdateTargets(Targets, TrainingGame, MaxTarget);
}
// CHANGE END
}
Console.WriteLine("Game over!");
DisplayScore(Score);
22) When a target is cleared, put a £ symbol in its position in the target list. When the £ symbol reaches the end of the tracker, increase the score by 1.
C#:
C# -
________________________________________________________________
23) Implement a victory condition which allows the player to win the game by achieving a certain score. Allow the user to pick difficulty, e.g. easy (10), normal (20), hard (40).
24) Shotgun. If an expression exactly evaluates to a target, the score is increased by 3 and remove the target as normal. If an evaluation is within 1 of the target, the score is increased by 1 and remove those targets too.
25) Every time the user inputs an expression, shuffle the current position of all targets (cannot push a number closer to the end though).
26) Speed Demon. Implement a mode where the target list moves a number of places equal to the current player score. Instead of ending the game when a target gets to the end of the tracker, subtract 1 from their score. If their score ever goes negative, the player loses.
27) Allow the user to save the current state of the game using a text file and implement the ability to load up a game when they begin the program.
28) Multiple of X. The program should randomly generate a number each turn, e.g. 3 and if the user creates an expression which removes a target which is a multiple of that number, give them a bonus of their score equal to the multiple (in this case, 3 extra score).
29) Validate a user's entry to confirm their choice before accepting an expression.
30) Prime time punch. If the completed target was a prime number, destroy the targets on either side of the prime number (count them as scored).
31) Josh Lord.
32) make the program object oriented
33) do not use reverse polish notation
34) Allow the user to specify the highest number within the five NumbersAllowed.
35) Allow the user to save and reload the game.
Python:
This solution focuses on logging all values that had been printed the previous game, overwriting the score, and then continuing the game as before. A game log can be saved, reloaded and then continued before being saved again without loss of data.
Add selection (if) statement at the top of PlayGame() to allow for user to input desired action
Score = 0
GameOver = False
if (input("Load last saved game? (y/n): ").lower() == "y"):
with open("savegame.txt", "r") as f:
lines = []
for line in f:
lines.append(line)
print(line)
Score = re.search(r'\d+', lines[-2])
else:
open("savegame.txt", 'w').close()
while not GameOver:Change DisplayScore(), DisplayNumbersAllowed() and DisplayTargets() to allow for the values to be returned instead of being printed.
def DisplayScore(Score):
output = str("Current score: " + str(Score))
print(output)
print()
print()
return output
def DisplayNumbersAllowed(NumbersAllowed):
list_of_numbers = []
for N in NumbersAllowed:
list_of_numbers.append((str(N) + " "))
output = str("Numbers available: " + "".join(list_of_numbers))
print(output)
print()
print()
return output
def DisplayTargets(Targets):
list_of_targets = []
for T in Targets:
if T == -1:
list_of_targets.append(" ")
else:
list_of_targets.append(str(T))
list_of_targets.append("|")
output = str("|" + "".join(list_of_targets))
print(output)
print()
print()
return outputPrint returned values, as well as appending to the save file. <syntaxhighlight> def DisplayState(Targets, NumbersAllowed, Score):
DisplayTargets(Targets)
DisplayNumbersAllowed(NumbersAllowed)
DisplayScore(Score)
try:
with open("savegame.txt", "a") as f:
f.write(DisplayTargets(Targets) + "\n\n" + DisplayNumbersAllowed(NumbersAllowed) + "\n\n" + DisplayScore(Score) + "\n\n")
except Exception as e:
print(f"There was an exception: {e}")
</syntaxhighlighting>