java - Need to show "Insufficient Funds" for negative amounts -

i need throw exception "insufficient funds" when user withdrawals more amount in initialaccountbalance (which equals 500.00). however, unsure put exception.

public static void main(string[] args) {      scanner in = new scanner(system.in);      double initialaccountbalance = 500.00;      system.out.print("enter transaction type (balance, deposit, or withdrawal): ");     string transactiontype = in.nextline();      if (transactiontype.equalsignorecase("balance")){         system.out.println("balance " +initialaccountbalance);         system.out.println();      } else if (transactiontype.equalsignorecase("deposit")){         system.out.println("enter deposit: ");         int deposit = in.nextint();         double balance = initialaccountbalance + deposit;         system.out.printf("account balance: %8.2f", balance);      } else if(transactiontype.equalsignorecase("withdrawal")){         system.out.println("enter withdrawal: ");         int withdrawal = in.nextint();         double balance = initialaccountbalance - withdrawal;         system.out.printf("account balance: %8.2f", balance);      } else {         system.out.println("invalid transaction type");     } } 

you place if right after user enters amount withdrawal this:

//... system.out.println("enter withdrawal: "); int withdrawal = in.nextint(); if (withdrawal > initialaccountbalance)     throw new runtimeexception("insufficient funds"); double balance = initialaccountbalance - withdrawal; system.out.printf("account balance: %8.2f", balance); //... 

if want throw own exception have create new class extends exception @chenchuk mentioned in comments.

public class insufficientfundsexception extends exception{     //if need can overwrite method of exception here } 

so can throw insufficientfundsexception in main method:

//... system.out.println("enter withdrawal: "); int withdrawal = in.nextint(); if (withdrawal > initialaccountbalance)     throw new insufficientfundsexception(); double balance = initialaccountbalance - withdrawal; system.out.printf("account balance: %8.2f", balance); //... 

but have provide way of handling exception either using try-catch block or adding throws declaration method head. should up, it's explain in depth here...

hope helps bit (: