Java 如何将参数值从一个方法传递到同一类中的另一个方法
我正在为ATM模拟机编写这段代码,它具有存款、取款和余额查询功能。代码需要使用方法而不是switch语句编写。 我的存款方式有效,但我对取款和余额查询方式都有问题。我希望所有方法都能访问checkAc_bal,以便执行计算。我对Java是个新手,我正试图对方法和行为了如指掌。非常感谢Java 如何将参数值从一个方法传递到同一类中的另一个方法,java,methods,parameter-passing,pass-by-reference,Java,Methods,Parameter Passing,Pass By Reference,我正在为ATM模拟机编写这段代码,它具有存款、取款和余额查询功能。代码需要使用方法而不是switch语句编写。 我的存款方式有效,但我对取款和余额查询方式都有问题。我希望所有方法都能访问checkAc_bal,以便执行计算。我对Java是个新手,我正试图对方法和行为了如指掌。非常感谢 将其定义为类成员: import java.util.Scanner; public class Main { static int checkAc_bal = 0; //<----------
将其定义为类成员:
import java.util.Scanner;
public class Main
{
static int checkAc_bal = 0; //<------------------------add this
public static void showMenu()
{
Scanner sc = new Scanner(System.in) ;
String input = null ;
do
{
input = showOptions(sc) ;
if(input != null)
{
switch(input.trim())
{
case "1" : deposit(sc) ;
break ;
case "2" : withdraw(sc);
break ;
case "3" : balanceInquiry() ;
break ;enter code here
case "4" : System.exit(0);
default : System.out.println("Wrong option entered. Exiting application") ;
System.exit(0);
}
}
}while(true) ;
}
public static String showOptions(Scanner sc)
{
System.out.println("********************Welcome to ATM Machine******************** ");
System.out.println("Enter Option");
System.out.println("1. Deposit");
System.out.println("2. Withdrawal");
System.out.println("3. Balance Inquiry");
System.out.println("4. Exit\n");
String input = sc.nextLine() ;
return input ;
}
public static void deposit (Scanner sc) {
// int checkAc_bal = 0; <---------------- remove this
System.out.print("Enter amount to be deposited:");
int deposit;
Scanner s = new Scanner(System.in);
deposit = s.nextInt();
//int checkAc_bal = 0;
checkAc_bal = checkAc_bal + deposit;
System.out.println("Your Money has been successfully deposited");
System.out.println("Balance: " +checkAc_bal);
}
public static void withdraw (Scanner sc){
System.out.print("Enter money to be withdrawn:");
int withdraw;
Scanner s = new Scanner(System.in);
withdraw = s.nextInt();
if(withdraw<=checkAc_bal)
{
checkAc_bal = checkAc_bal - withdraw;
System.out.println("Please collect your money");
}
else
{
System.out.println("Insufficient Balance");
}
System.out.println("");
}
public static void balanceInquiry () {
System.out.println("Balance: " + checkAc_bal);
}
public static void main(String[] args) {
showMenu();
}
}
如果希望int可以被其他方法访问,则需要在整个类的范围内而不是在方法内声明它。尝试在主类中声明checkAc_bal。您有三个问题,下面是答案: 将变量全局声明为可从所有方法访问。 不要使用开关盒,否则需要使用 如何将参数传递给同一类中的方法? 我看到您已经在代码中这样做了。您通过参数调用了其他方法,并收到了它们。 或者很好地提出你的问题,比如你到底需要什么 下面是完整的代码:
import java.util.Scanner;
public class Main{
static int checkAc_bal = 0; // <---- declare on class scope
public static void showMenu() {
Scanner sc = new Scanner(System.in) ;
String input = null ;
do {
input = showOptions(sc) ;
if(input != null) {
// removed the switch-case and if-else used
if(input.trim().equals("1")) {deposit();}
else if(input.trim().equals("2")) {withdraw();}
else if(input.trim().equals("3")) {balanceInquiry();}
else if(input.trim().equals("4")) {System.exit(0);}
else {
System.out.println("Wrong option entered. Exiting application") ;
System.exit(0);
}
}
}while(true) ;
}
public static String showOptions(Scanner sc){
System.out.println("********************Welcome to ATM Machine******************** ");
System.out.println("Enter Option");
System.out.println("1. Deposit");
System.out.println("2. Withdrawal");
System.out.println("3. Balance Inquiry");
System.out.println("4. Exit\n");
String input = sc.nextLine() ;
return input ;
}
public static void deposit () {
System.out.print("Enter amount to be deposited:");
int deposit;
Scanner s = new Scanner(System.in);
deposit = s.nextInt();
checkAc_bal = checkAc_bal + deposit;
System.out.println("Your Money has been successfully deposited");
System.out.println("Balance: " +checkAc_bal);
}
public static void withdraw (){
System.out.print("Enter money to be withdrawn:");
int withdraw;
Scanner s = new Scanner(System.in);
withdraw = s.nextInt();
if(withdraw<=checkAc_bal) {
checkAc_bal = checkAc_bal - withdraw;
System.out.println("Please collect your money");
} else {
System.out.println("Insufficient Balance");
}
System.out.println("");
}
public static void balanceInquiry () {
System.out.println("Balance: " + checkAc_bal);
}
public static void main(String[] args) {
showMenu();
}
}
理解将在类范围内声明的checkAc_bal,但您对开关盒的要求不清楚。
import java.util.Scanner;
public class Main{
static int checkAc_bal = 0; // <---- declare on class scope
public static void showMenu() {
Scanner sc = new Scanner(System.in) ;
String input = null ;
do {
input = showOptions(sc) ;
if(input != null) {
// removed the switch-case and if-else used
if(input.trim().equals("1")) {deposit();}
else if(input.trim().equals("2")) {withdraw();}
else if(input.trim().equals("3")) {balanceInquiry();}
else if(input.trim().equals("4")) {System.exit(0);}
else {
System.out.println("Wrong option entered. Exiting application") ;
System.exit(0);
}
}
}while(true) ;
}
public static String showOptions(Scanner sc){
System.out.println("********************Welcome to ATM Machine******************** ");
System.out.println("Enter Option");
System.out.println("1. Deposit");
System.out.println("2. Withdrawal");
System.out.println("3. Balance Inquiry");
System.out.println("4. Exit\n");
String input = sc.nextLine() ;
return input ;
}
public static void deposit () {
System.out.print("Enter amount to be deposited:");
int deposit;
Scanner s = new Scanner(System.in);
deposit = s.nextInt();
checkAc_bal = checkAc_bal + deposit;
System.out.println("Your Money has been successfully deposited");
System.out.println("Balance: " +checkAc_bal);
}
public static void withdraw (){
System.out.print("Enter money to be withdrawn:");
int withdraw;
Scanner s = new Scanner(System.in);
withdraw = s.nextInt();
if(withdraw<=checkAc_bal) {
checkAc_bal = checkAc_bal - withdraw;
System.out.println("Please collect your money");
} else {
System.out.println("Insufficient Balance");
}
System.out.println("");
}
public static void balanceInquiry () {
System.out.println("Balance: " + checkAc_bal);
}
public static void main(String[] args) {
showMenu();
}
}
********************Welcome to ATM Machine********************
Enter Option
1. Deposit
2. Withdrawal
3. Balance Inquiry
4. Exit
1
Input : 1
Enter amount to be deposited:100
Your Money has been successfully deposited
Balance: 100
********************Welcome to ATM Machine********************
Enter Option
1. Deposit
2. Withdrawal
3. Balance Inquiry
4. Exit
1
Input : 1
Enter amount to be deposited:200
Your Money has been successfully deposited
Balance: 300
********************Welcome to ATM Machine********************
Enter Option
1. Deposit
2. Withdrawal
3. Balance Inquiry
4. Exit
1
Input : 1
Enter amount to be deposited:200
Your Money has been successfully deposited
Balance: 500
********************Welcome to ATM Machine********************
Enter Option
1. Deposit
2. Withdrawal
3. Balance Inquiry
4. Exit
3
Input : 3
Balance: 500
********************Welcome to ATM Machine********************
Enter Option
1. Deposit
2. Withdrawal
3. Balance Inquiry
4. Exit