如何在Java中为掷硬币游戏创建连续循环

Question

我在尝试使代码循环并重新执行程序时遇到问题，直到用户要求他们输入零为止。我尝试了一段时间的语句，但我不确定我是否正确地实现了它，因为我得到的只是错误。我感谢所有能提供的帮助。我在下面包含了我的代码。

public class CoinTossing {
public static void main(String[] args) {
//Scanner method
Scanner input = new Scanner(System.in);
int choice;
System.out.println("Welcome to the Coin Toss Program.");
//Variables for the count of heads and tails.
int headCount = 0;
int tailCount = 0;
System.out.println("How many coin flips do you want to do?");
int number = input.nextInt();
for (int i = 1; i <= number; i++) {
Random rand = new Random();
// Simulate the coin tosses.
for (int count = 0; count < number; count++) {
if (rand.nextInt(2) == 0) {
tailCount++;
} else {
headCount++;
}
}
System.out.println("Times head was flipped:" + headCount);
System.out.println("Times tail was flipped:" + tailCount);
return;
}
}
}

Answer 1

您的主要方法可能如下所示：

public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Welcome to the Coin Toss Program.");
//Variables for the count of heads and tails.

while (true) {
int headCount = 0;
int tailCount = 0;
System.out.println("How many coin flips do you want to do?");
int number = input.nextInt();
if (number == 0) { break; }
Random rand = new Random();
// Simulate the coin tosses.
for (int i = 0; i < number; i++) {
if (rand.nextInt(2) == 0) {
tailCount++;
} else {
headCount++;
}
}

System.out.println("Times head was flipped:" + headCount);
System.out.println("Times tail was flipped:" + tailCount);
}
}

这里，while循环是在欢迎消息之后输入的，只有当用户输入0时才会退出模拟。

检索到用户输入后，它将检查用户输入是否为0。如果用户输入0，它将在程序模拟掷硬币之前的while循环break：

if (number == 0) { break; }

Answer 2

将代码放入while循环中，但以下两行除外：

Scanner input = new Scanner(System.in);
System.out.println("Welcome to the Coin Toss Program.");

在掷硬币游戏结束时，事情的自然顺序是询问用户是否想再次玩。这允许用户退出应用程序，而不是陷入连续循环：

String yn = "y";
while (yn.equalsIgnoreCase("y")) {
int headCount = 0;
int tailCount = 0;
int number = 0;
String num = null;
while (num == null) {
System.out.print("How many coin flips do you want to do? --> ");
num = input.nextLine();
if (!num.matches("\d+")) {
System.err.println("Invalid Integer Number Supplied (" 
+ num + ")! Try Again...");
System.out.println();
num = null;
}
}
number = Integer.valueOf(num);
// Simulate the coin tosses.
for (int i = 1; i <= number; i++) {
if (rand.nextInt(2) == 0) {
tailCount++;
}
else {
headCount++;
}
}
System.out.println("Times head was flipped:" + headCount);
System.out.println("Times tail was flipped:" + tailCount);
System.out.println();
while (yn.equalsIgnoreCase("y")) {
System.out.print("Do you want to play again? (y/n) --> ");
yn = input.nextLine();
if (yn.matches("[yYnN]")) {
System.out.println();
break;
}
else {
System.err.println("Invalid response (" + yn + ")! 'y' or 'n' only!");
System.out.println();
yn = "y";
}
}
}

整个应用程序可能看起来像这样：

public class CoinTossing {
public static void main(String[] args) {
java.util.Scanner input = new java.util.Scanner(System.in);
java.util.Random rand = new java.util.Random();
System.out.println("Welcome to the Coin Toss Program");
System.out.println("================================");
System.out.println();
String yn = "y";
while (yn.equalsIgnoreCase("y")) {
int headCount = 0;
int tailCount = 0;
int number = 0;
String num = null;
while (num == null) {
System.out.print("How many coin flips do you want to do? --> ");
num = input.nextLine();
if (!num.matches("\d+")) {
System.err.println("Invalid Integer Number Supplied (" 
+ num + ")! Try Again...");
System.out.println();
num = null;
}
}
number = Integer.valueOf(num);
// Simulate the coin tosses.
for (int i = 1; i <= number; i++) {
if (rand.nextInt(2) == 0) {
tailCount++;
}
else {
headCount++;
}
}
System.out.println("Times head was flipped:" + headCount);
System.out.println("Times tail was flipped:" + tailCount);
System.out.println();
while (yn.equalsIgnoreCase("y")) {
System.out.print("Do you want to play again? (y/n) --> ");
yn = input.nextLine();
if (yn.matches("[yYnN]")) {
System.out.println();
break;
}
else {
System.err.println("Invalid response (" + yn + ")! 'y' or 'n' only!");
System.out.println();
yn = "y";
}
}
}
}
}