Java first Knowledge--process Control

1, If/else SELECT statement.

Its grammatical form is:

if (Boolean expression) {

Executes when the Boolean expression is True

}

else{

Executes when the Boolean expression is False

}

2, Do/while Loop statement.

Its grammatical form is:

do {

Statement

} while (Boolean expression);

3, using the above two statements to write a simple bank ATM System Center.

code example:

public static void Main (string[] args) {
System.out.println ("Welcome to China Bank ATM System Center");
Scanner input = new Scanner (system.in);
int count = 0;//user input error password count
String name = "Xiaoming";//Registered user name
String PassWord = "12345678";//user-Set Password
String UserName;//user-entered user name
String UserPassword;//password entered by the user
Double money = 9999,money2,money3;//money is the balance, Money2 is the deposit amount; Money3 is the withdrawal amount;
String str = "";//str Storage user's Choice (y/n)
//Login Interface
do {
count++;
if (count>1&&count<4) {
SYSTEM.OUT.PRINTLN ("Input error, you also have" + (4-count) + "Times login opportunity, press ENTER to continue! ");
}
SYSTEM.OUT.PRINTLN ("Please login");
System.out.print ("User name:");
UserName = input. Next ();
System.out.print ("Password:");
UserPassword = input. Next ();
if (count==3)
Break//Password error over 3 times, loop over
} while (! ( Name.equals (UserName) &&password.equals (UserPassword));
if (count = = 3) {
System.out.println ("Your account has been locked! ");//Login error
}else{//Login successful, enter the service main interface
do{
SYSTEM.OUT.PRINTLN ("Please select service:");
System.out.println ("1, check balance" + "\ T" + "2, withdrawal" + "\ T" + "3, deposit" + "\ T");
int num =input. nextint ();//USER Select service
//service 1, check the balance
if (num = = 1) {
System.out.println ("Your balance is:" +money);
System.out.print ("Y back to main interface, n exit system!") Please select (y/n): ");
str = Input.next ();
}
//Services 2, withdrawals
if (num = = 2) {
System.out.print ("Please enter the withdrawal amount:");
Money2 = input. nextdouble ();
if (Money2 <= money&&money2>0) {
Money = Money-money2;
SYSTEM.OUT.PRINTLN ("Withdrawals are successful! ");
System.out.print ("Y back to main interface, n exit system!") Please select (y/n): ");
str = Input.next ();
}else{
SYSTEM.OUT.PRINTLN ("The amount you have entered is incorrect! ");
System.out.print ("Y back to main interface, n exit system!") Please select (y/n): ");
str = Input.next ();
}
}
//Service 3, deposit
if (num = = 3) {
System.out.print ("Please enter Deposit Amount:");
Money3 = input. nextdouble ();
Money = Money+money3;
System.out.println ("Deposit success! ");
System.out.print ("Y back to main interface, n exit system!") Please select (y/n): ");
str = Input.next ();
}
}
while (Str.equals ("Y") | | Str.equals ("Y"));//Based on user selection, decide whether to return to the main interface
System.out.println ("Welcome next visit!!!");//Exit system
}
}

}

Java primary Knowledge-process Control