Question

In: Computer Science

Working on a program but nothing is being sent to the output file. How can I...

Working on a program but nothing is being sent to the output file. How can I fix this?

import java.util.Scanner;
import java.io.*;

public class Topic7Hw {

   static Scanner sc = new Scanner (System.in);
  
   public static void main(String[] args) throws IOException {
      
       PrintWriter outputFile = new PrintWriter ("output.txt");
      
       outputFile.println("hello");
      
       final int MAX_NUM = 10;
   int[] acctNum = new int[MAX_NUM];
   double[] balance = new double[MAX_NUM];
  
   System.out.print("Enter number of initial account: ");
   int numAccts = sc.nextInt();
  
   readAccts(acctNum, balance, numAccts);
     
  
   //infinite loop
   while(true)
   {
   menu();
  
   System.out.print("Enter option: ");
   char ch = sc.next().charAt(0);
  
   //switch statement
   switch(ch)
   {
   case 'W': case 'w':
   withdrawal(acctNum, balance, numAccts);
   break;
   case 'D': case 'd':
   deposit(acctNum, balance, numAccts);
   break;
   case 'N': case 'n':
   numAccts = newAcct(acctNum, balance, numAccts);
   break;
   case 'B': case 'b':
   balance(acctNum, balance, numAccts);
   break;
   case 'Q': case 'q':
   System.exit(0);
   case 'X': case 'x':
   numAccts = deleteAcct(acctNum, balance, numAccts);
   default:
   System.out.println("Wrong option. Try again.");
     
     
   }
   outputFile.close();
   }  

   }
  
   public static void menu() throws IOException{
      
       System.out.println("Select one of the following:");
   System.out.println("W - Withdrawal");
   System.out.println("D - Deposit");
   System.out.println("N - New account");
   System.out.println("B - Balance");
   System.out.println("Q - Quit");
   System.out.println("X - Delete Account");
     
   }
  
public static void withdrawal(int[] acctNum, double[] balance, int numAccts)
   throws IOException {
     
   System.out.print("Enter account number: ");
   int account = sc.nextInt();
  
   int i= findAcct(acctNum, numAccts, account);
   if(i==-1)
   {
   System.out.print("Invalid account");
   return;
   }
  
   System.out.print("Enter withdrawal amount: $");
   double amount = sc.nextDouble();
   if(amount<=0)
   {
   System.out.print("Invalid amount");
   return;
   }
  
   System.out.println("Transaction Type: withdrawal");
   System.out.println("Account Number: " + acctNum[i]);
   System.out.println("Amount to withdrawal: $" + amount);
   System.out.println("Old Balance: $" + balance[i]);
   balance[i] = balance[i] - amount;
   System.out.println("New Balance: $" + balance[i]);
     
   }

public static void deposit(int[] acctNum, double[] balance, int maxAccts)
throws IOException {
System.out.print("Enter account number: ");
int account = sc.nextInt();
  
int i = findAcct(acctNum, maxAccts, account);
if(i==-1)
{
System.out.print("Invalid account");
return;
}
  
System.out.print("Enter deposit amount: $");
double amount = sc.nextDouble();
if(amount<=0)
{
System.out.print("Invalid amount");
return;
}
  
System.out.println("Transaction Type: Deposit");
System.out.println("Account Number: " + acctNum[i]);
System.out.println("Amount to Deposit: $" + amount);
System.out.println("Old Balance: $" + balance[i]);
balance[i] = balance[i] + amount;
System.out.println("New Balance: $" + balance[i]);

}

public static int newAcct(int[] acctNum, double[] balance, int numAccts)
throws IOException {
  
System.out.print("Enter account number: ");
int acct = sc.nextInt();
  
int k = findAcct(acctNum, numAccts, acct);
  
if(k!=-1)
{
System.out.print("Account already exist!");
return numAccts;
}
  
acctNum[numAccts] = acct;
  
balance[numAccts] = 0;
  
return numAccts+1;
}

public static void balance(int[] acctNum, double[] balance, int numAccts)
throws IOException {
  
System.out.print("Enter account number: ");
int acct = sc.nextInt();
  
int i = findAcct(acctNum, numAccts, acct);
  
if(i==-1)
{
System.out.print("Invalid account");
return;
}
  
System.out.println("Account Number: " + acctNum[i]);
System.out.println("Balance: $" + balance[i]);
}

public static int deleteAcct(int[] acctNum, double[] balance, int numAccts)
throws IOException {
System.out.print("Enter account number: ");
int account = sc.nextInt();
  
int k = findAcct(acctNum, numAccts, account);
if(k==-1 || balance[k]!=0)
{
System.out.print("Invalid account");
return numAccts;
}
  
for(int i=k; i<numAccts-1; i++)
{
acctNum[i] = acctNum[i+1];
balance[i] = balance[i+1];
}
  
return numAccts-1;
}

public static void readAccts(int[] acctNum, double[] balance, int maxAccts)
throws IOException {
for(int i=0; i<maxAccts; i++)
{
System.out.print("Enter account number: ");
acctNum[i] = sc.nextInt();
System.out.print("Enter initial balance: $");
balance[i] = sc.nextDouble();
}
}

public static void printAccts(int[] acctNum, double[] balance, int maxAccts)
throws IOException {
System.out.println("Account number Balance ");

PrintWriter outputFile = new PrintWriter ("output.txt");

outputFile.print("Account number Balance ");
for(int i=0; i<maxAccts; i++)
{
System.out.println(acctNum[i] + "\t$" + balance[i]);

outputFile.print(acctNum[i] + "\t$" + balance[i]);
}

outputFile.close();
}

public static int findAcct(int[] acctNum, int maxAccts, int account)
throws IOException {
for(int i=0; i<maxAccts; i++)
{
if(acctNum[i]==account)
return i;
}
return -1;
}


}

Solutions

Expert Solution

Dear Student,

You have to flush the stream. Thats the part missing in your code.

....

....

public static void main(String[] args) throws IOException {

  

   PrintWriter outputFile = new PrintWriter ("output.txt");

  

   outputFile.println("hello");

   outputFile.flush(); // Add this line where ever you want to print.

   final int MAX_NUM = 10;

   int[] acctNum = new int[MAX_NUM];

   double[] balance = new double[MAX_NUM];

...

...

Happy Learning.

Update as per Ask :

import java.util.Scanner;

import java.io.*;

import java.util.Scanner;

import java.io.*;

public class Topic7Hw {

   static Scanner sc = new Scanner (System.in);

  

   public static void main(String[] args) throws IOException {

  

   PrintWriter outputFile = new PrintWriter ("output.txt");

  

   outputFile.println("hello");

  

   final int MAX_NUM = 10;

   int[] acctNum = new int[MAX_NUM];

   double[] balance = new double[MAX_NUM];

  

   System.out.print("Enter number of initial account: ");

   int numAccts = sc.nextInt();

  

   readAccts(acctNum, balance, numAccts);

   printAccts(acctNum, balance, numAccts);

  

   //infinite loop

   while(true)

   {

   menu();

  

   System.out.print("Enter option: ");

   char ch = sc.next().charAt(0);

  

   //switch statement

   switch(ch)

   {

   case 'W': case 'w':

   withdrawal(acctNum, balance, numAccts);

   break;

   case 'D': case 'd':

   deposit(acctNum, balance, numAccts);

   break;

   case 'N': case 'n':

   numAccts = newAcct(acctNum, balance, numAccts);

   break;

   case 'B': case 'b':

   balance(acctNum, balance, numAccts);

   break;

   case 'Q': case 'q':

   System.exit(0);

   case 'X': case 'x':

   numAccts = deleteAcct(acctNum, balance, numAccts);

   default:

   System.out.println("Wrong option. Try again.");

   }

   outputFile.close();

   }

   }

  

   public static void menu() throws IOException{

  

   System.out.println("Select one of the following:");

   System.out.println("W - Withdrawal");

   System.out.println("D - Deposit");

   System.out.println("N - New account");

   System.out.println("B - Balance");

   System.out.println("Q - Quit");

   System.out.println("X - Delete Account");

   }

  

public static void withdrawal(int[] acctNum, double[] balance, int numAccts)

   throws IOException {

   System.out.print("Enter account number: ");

   int account = sc.nextInt();

  

   int i= findAcct(acctNum, numAccts, account);

   if(i==-1)

   {

   System.out.print("Invalid account");

   return;

   }

  

   System.out.print("Enter withdrawal amount: $");

   double amount = sc.nextDouble();

   if(amount<=0)

   {

   System.out.print("Invalid amount");

   return;

   }

  

   System.out.println("Transaction Type: withdrawal");

   System.out.println("Account Number: " + acctNum[i]);

   System.out.println("Amount to withdrawal: $" + amount);

   System.out.println("Old Balance: $" + balance[i]);

   balance[i] = balance[i] - amount;

   System.out.println("New Balance: $" + balance[i]);

   }

public static void deposit(int[] acctNum, double[] balance, int maxAccts)

throws IOException {

System.out.print("Enter account number: ");

int account = sc.nextInt();

  

int i = findAcct(acctNum, maxAccts, account);

if(i==-1)

{

System.out.print("Invalid account");

return;

}

  

System.out.print("Enter deposit amount: $");

double amount = sc.nextDouble();

if(amount<=0)

{

System.out.print("Invalid amount");

return;

}

  

System.out.println("Transaction Type: Deposit");

System.out.println("Account Number: " + acctNum[i]);

System.out.println("Amount to Deposit: $" + amount);

System.out.println("Old Balance: $" + balance[i]);

balance[i] = balance[i] + amount;

System.out.println("New Balance: $" + balance[i]);

}

public static int newAcct(int[] acctNum, double[] balance, int numAccts)

throws IOException {

  

System.out.print("Enter account number: ");

int acct = sc.nextInt();

  

int k = findAcct(acctNum, numAccts, acct);

  

if(k!=-1)

{

System.out.print("Account already exist!");

return numAccts;

}

  

acctNum[numAccts] = acct;

  

balance[numAccts] = 0;

  

return numAccts+1;

}

public static void balance(int[] acctNum, double[] balance, int numAccts)

throws IOException {

  

System.out.print("Enter account number: ");

int acct = sc.nextInt();

  

int i = findAcct(acctNum, numAccts, acct);

  

if(i==-1)

{

System.out.print("Invalid account");

return;

}

  

System.out.println("Account Number: " + acctNum[i]);

System.out.println("Balance: $" + balance[i]);

}

public static int deleteAcct(int[] acctNum, double[] balance, int numAccts)

throws IOException {

System.out.print("Enter account number: ");

int account = sc.nextInt();

  

int k = findAcct(acctNum, numAccts, account);

if(k==-1 || balance[k]!=0)

{

System.out.print("Invalid account");

return numAccts;

}

  

for(int i=k; i<numAccts-1; i++)

{

acctNum[i] = acctNum[i+1];

balance[i] = balance[i+1];

}

  

return numAccts-1;

}

public static void readAccts(int[] acctNum, double[] balance, int maxAccts)

throws IOException {

for(int i=0; i<maxAccts; i++)

{

System.out.print("Enter account number: ");

acctNum[i] = sc.nextInt();

System.out.print("Enter initial balance: $");

balance[i] = sc.nextDouble();

}

}

public static void printAccts(int[] acctNum, double[] balance, int maxAccts)

throws IOException {

System.out.println("Account number Balance ");

PrintWriter outputFile = new PrintWriter ("output.txt");

outputFile.print("Account number Balance ");

for(int i=0; i<maxAccts; i++)

{

System.out.println(acctNum[i] + "\t$" + balance[i]);

outputFile.print(acctNum[i] + "\t$" + balance[i]);

}

outputFile.close();

}

public static int findAcct(int[] acctNum, int maxAccts, int account)

throws IOException {

for(int i=0; i<maxAccts; i++)

{

if(acctNum[i]==account)

return i;

}

return -1;

}

}

venereology answered 6 months ago
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