我正在尝试编写一个程序来读取多个用户银行帐户的信息并对它们执行某些操作（取款、存款、显示余额）等。代码似乎是正确的，但我对 .nextInt 有疑问();方法。这是我的代码。
import java.io.*;
import java.util.Scanner;
public class Topic_7_HW {
public static void printAcct(Scanner inputFile, PrintWriter outputFile, int[] acctNum, double[] balance,
int numAccts) {
for (int n = 0; n <= numAccts; n++) {
outputFile.printf("\n %1f Account Number: ", acctNum[n]);
outputFile.printf("\n %1f Account Balance: ", balance[n]);
}
}
public static int readAccts(Scanner inputFile, PrintWriter outputFile, int[] acctNum, double[] balance) {
int numAccts = 0;
while (inputFile.hasNext()) {
acctNum[numAccts] = inputFile.nextInt();
balance[numAccts] = inputFile.nextDouble();
numAccts++;
}
return numAccts;
}
public static int findAcct(Scanner inputFile, PrintWriter outputFile, int[] acctNum, int numAccts, int account) {
account = inputFile.nextInt();
if (account != -1) {
for (int n = 0; n <= numAccts; n++) {
if (account == acctNum[n])
;
account = acctNum[n];
}
} else
outputFile.printf("\n %1s Error; requested account does not exist. ");
return account;
}
public static void withdrawal(Scanner inputFile, PrintWriter outputFile, int[] acctNum, double[] balance,
int numAccts) {
int account = -1;
double wd = -1.0;
account = findAcct(inputFile, outputFile, acctNum, numAccts, account);
boolean acct_vld;
if (account != -1)
acct_vld = true;
if (acct_vld = true) {
outputFile.printf(
"%1d Withdrawing money from account ID: \n%1d Current balance: \n %1d Enter amount to withdraw: ",
acctNum[account], balance[account], wd);
wd = inputFile.nextDouble();
if (balance[account] < wd)
outputFile.printf("\n %1s Invalid withdraw ammount: Amount cannot exceed balance. ");
if (wd < 0)
outputFile.printf("\n %1s Invalid withdraw ammount: Cannot withdraw negative dollars. ");
else {
balance[account] -= wd;
outputFile.print("\n%1s Successfully withdrew $" + wd + " from account " + account);
}
}
}
public static void deposit(Scanner inputFile, PrintWriter outputFile, int[] acctNum, double[] balance,
int numAccts) {
int account = -1;
double dp = 0;
account = findAcct(inputFile, outputFile, acctNum, numAccts, account);
boolean acct_vld;
if (account != -1)
acct_vld = true;
else
acct_vld = false;
if (acct_vld = true) {
outputFile.printf(
"%1d Depositing money into account ID: \n%1d Current balance: \n %1d Enter amount to deposit: ",
acctNum[account], balance[account], dp);
dp = inputFile.nextDouble();
if (dp < 0 || dp == 0)
outputFile.printf("\n %1s Invalid withdraw ammount: Cannot withdraw negative/zero dollars. ");
else {
balance[account] += dp;
}
outputFile.print("\n%1s Successfully deposited $" + dp + " Into account " + account + ". new balance is: "
+ balance[account] + ".");
}
}
public static int newAcct(Scanner testCases, PrintWriter outputFile, int[] acctNum, double[] balance,
int numAccts) {
int account = -1;
boolean exist;
outputFile.printf("Creating New account. \n Please enter account number.");
for (int n = 0; n <= numAccts; n++) {
if (account == acctNum[n])
;
exist = true;
}
if (exist = true) {
outputFile.printf("\nChoose new ID. Account already exists.");
return account;
} else {
acctNum[account] = testCases.nextInt();
balance[account] = testCases.nextDouble();
outputFile.printf("\n Account successfully created. Account number is: %1d Current Balance is %1.2d",
acctNum[account], balance[account]);
return account;
}
}
public static void balance(Scanner inputFile, PrintWriter outputFile, int[] acctNum, double[] balance,
int numAccts) {
int account = -1;
account = findAcct(inputFile, outputFile, acctNum, numAccts, account);
for (int n = 0; n <= numAccts; n++) {
if (account == acctNum[n]) {
account = acctNum[n];
outputFile.printf("%1d", balance[n]);
} else
outputFile.printf("%1s Error; requested account does not exist");
}
}
public static void menu() {
System.out.println("Please make a selection.");
System.out.println("W - Withdraw");
System.out.println("D - Deposit");
System.out.println("B - Check Balance");
System.out.println("N - Make New Account");
System.out.println("Q - Quit");
}
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
PrintWriter outputFile;
outputFile = new PrintWriter("hw_7_out.txt");
File myinputFile = new File("C:\\Users\\chroZ\\eclipse-workspace\\Topic_7\\src\\hw7input.txt");
Scanner inputFile = new Scanner(myinputFile);
File mytestcases = new File("C:\\Users\\chroZ\\eclipse-workspace\\Topic_7\\src\\hw7testcases.txt");
Scanner testCases = new Scanner(mytestcases);
char slct;
final int max_acct = 50;
int notDone = 20;
double[] balance;
balance = new double[max_acct];
int[] acctNum;
acctNum = new int[max_acct];
int numAccts;
numAccts = readAccts(inputFile, outputFile, acctNum, balance);
// create a loop that calls the menu method and calls the selected action method
do {
menu();
String choice = testCases.next();
slct = choice.charAt(0);
switch (slct) {
// tell switch statement which method to call depending on the user's input
case 'W', 'w': withdrawal(inputFile, outputFile, acctNum, balance, numAccts);
break;
case 'D', 'd': deposit(inputFile, outputFile, acctNum, balance, numAccts);
break;
case 'B', 'b': balance(inputFile, outputFile, acctNum, balance, numAccts);
break;
case 'N', 'n': newAcct(inputFile, outputFile, acctNum, balance, numAccts);
break;
// declare notDone as the numerical value for F if user wants to quit
case 'Q', 'q':
notDone = 6;
break;
// prints an error if the input is anything other than the availible selections
default:
outputFile.printf("\n%1s", "Error; Invalid selection.");
}
} while (notDone == 20);
printAcct(inputFile, outputFile, acctNum, balance, numAccts);
outputFile.printf("In total, there are " + numAccts + " accounts.");
outputFile.flush();
inputFile.close();
outputFile.close();
testCases.close();
}
}
这是从 inputFile 中读取的内容： 2616 19788.01 7187 3402.67 9685 210.99 1190 762062.84 9013 23186.65 2257 307.77 9062 16.4 8836 340837.14 9439 26802.80 2435 2025.25 7563 80687.21
它应该读取帐号并将其作为下一个 int，但相反，我在行上得到了一个 nosuchelementexception； 24、40 和 159 是（按顺序）：account = inputFile.nextInt(); - account = findAcct(inputFile, outputFile, acctNum, numAccts, account); - case 'W', 'w': withdrawal(inputFile, outputFile, acctNum, balance, numAccts);