Which method implementation correctly operates on the state safely?
hard🚀 Application Q15 of 15
C Sharp (C#) - Classes and Objects
You have a class BankAccount with a private field balance. You want to add a method Withdraw that subtracts an amount only if there is enough balance. Which method implementation correctly operates on the state safely?
Method should only subtract amount if balance is enough to avoid negative balance.
Step 2: Verify method behavior on insufficient funds
public void Withdraw(decimal amount) { if (amount <= balance) balance -= amount; else Console.WriteLine("Insufficient funds"); } checks amount <= balance and prints a message if not enough, preventing invalid state.
Final Answer:
public void Withdraw(decimal amount) { if (amount <= balance) balance -= amount; else Console.WriteLine("Insufficient funds"); } -> Option C
Quick Check:
Safe state update with condition = public void Withdraw(decimal amount) { if (amount <= balance) balance -= amount; else Console.WriteLine("Insufficient funds"); } [OK]
Quick Trick:Check balance before subtracting to avoid negative state [OK]
Common Mistakes:
MISTAKES
Subtracting without checking balance
Returning new value without updating state
Adding amount when negative instead of subtracting
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