A programmer is writing a game - AQA - GCSE Computer Science - Question 13 - 2023 - Paper 1
Question 13
A programmer is writing a game. The game uses a 3 x 3 grid containing nine squares.
In the game, a square on the grid is referred to by a letter and a number. For e... show full transcript
Worked Solution & Example Answer:A programmer is writing a game - AQA - GCSE Computer Science - Question 13 - 2023 - Paper 1
Step 1
Use the variable check
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Answer
Implement a boolean variable check initialized to false, which controls the loop for input validation.
Step 2
Provide the following steps until a valid grid reference is entered
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Answer
Use a while (check == false) loop to repeatedly prompt the user until a valid reference is received.
Step 3
Output an error if a grid reference
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Answer
Inside the loop, check the length of the string. If it's not equal to 2, print an error message and prompt for a new entry.
Step 4
Where the first character is not a valid letter
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Answer
Check if the first character is not among 'A', 'B', or 'C'. If true, display an error message indicating the valid characters.
Step 5
Where the second character is not a valid number
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Answer
Check if the second character is not among '1', '2', or '3'. If true, display an error message indicating the valid numbers.
Step 6
Show your code in a logically appropriate manner
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Answer
Here’s a sample implementation:
bool check = false;
while (check == false)
{
string square = "";
while (square.Length != 2)
{
Console.Write("Enter grid reference (eg C2): ");
square = Console.ReadLine();
square = square.ToUpper();
if (square.Length != 2)
{
Console.WriteLine("Error: Grid reference must be 2 characters.");
}
else if (square[0] < 'A' || square[0] > 'C')
{
Console.WriteLine("Error: First character must be A, B, or C.");
}
else if (square[1] < '1' || square[1] > '3')
{
Console.WriteLine("Error: Second character must be 1, 2, or 3.");
}
else
{
check = true; // Valid input received
}
}
}
This code nicely encapsulates the requirements for checking the grid reference.
