我正在尝试使项目成为天际线的一部分，并且似乎无法解决此do / while循环问题。我觉得我一直在面对这个问题，却没有注意到。 问题：我运行该程序，它到达标题，并询问您是否要播放（y / n），并检查输入的键是“ y”还是“ n”，如果不是，则程序会再次询问您（y / n）。一切正常，但是当程序结束时，do / while循环似乎重新开始，并询问您是否要“播放（y / n）”。 任何帮助都将是惊人的。对我愚蠢的自我表示歉意。我是编码的新手，并认为这将是一个有趣的项目。 代码：
import java.util.*;
public class skyrim {
public static void intro() {
Scanner input = new Scanner(System.in);
System.out.println("The intro...");
System.out.println("Continue... (x)");
String B = input.next();
if (B.startsWith("x")) {
for (int b = 0; b < 50; b++) {
System.out.println();
}
}
System.out.println("To the game...");
System.out.println("Continue... (x)");
String C = input.next();
if (C.startsWith("x")) {
for (int c = 0; c < 50; c++) {
System.out.println();
}
}
System.out.println("That is definitely not Skyrim...");
System.out.println("Continue... (x)");
String D = input.next();
if (D.startsWith("x")) {
for (int d = 0; d < 50; d++) {
System.out.println();
}
}
System.out.println("But actually totally is....");
System.out.println("Continue... (x)");
String E = input.next();
if (E.startsWith("x")) {
for (int e = 0; e < 50; e++) {
System.out.println();
}
}
skyrimlogo();
System.out.println("SKYRIM: The Quest of The Golden Claw");
//System.out.println("*boom boomboom BOOM*");
System.out.println("Bethesda please don't sue me.");
String next = "";
do {
System.out.println("Play (y/n)");
next = input.next();
if (next.startsWith("y")) {
awake(input);
}
if (next.startsWith("n")) {
System.out.println("Exiting Game...");
System.exit(0);
}
}
while (!next.startsWith("y") || !next.startsWith("n"));
}
public static void skyrimlogo() {
System.out.println(" /\\ /\\");
System.out.println(" / ( ) \\");
System.out.println(" / /\\) (/\\ \\");
System.out.println(" / / (\\ \\ \\");
System.out.println(" / / ; \\_/) \\ \\");
System.out.println(" / / (,-. ( \\ \\");
System.out.println(" / / ) ) \\ \\");
System.out.println(" / / ,-',' \\ \\");
System.out.println(" / / (\\( ( /) \\ \\");
System.out.println("/ '._____)\\) \\/(______,' \\");
System.out.println("\\ /");
System.out.println(" \\ .-. ,-. /");
System.out.println(" \\ / \\/\\ (\\/ \\ / ");
System.out.println(" \\ \\ \\ ) / / ");
System.out.println(" \\ \\ ) / ,' / ");
System.out.println(" \\ \\ / / | /");
System.out.println(" \\ \\ \\ \\ | /");
System.out.println(" \\ ) ) ) | /");
System.out.println(" \\ | / / (/");
System.out.println(" \\) / / ");
System.out.println(" / / /|");
System.out.println(" \\ \\_/ )");
System.out.println(" \\ / ");
System.out.println(" \\_/ ");
}
public static void awake(Scanner input) {
System.out.println("You awake to a cold morning on the back of a cart pulled by a pair of horses.");
//wagon();
System.out.println("Continue... (x)");
String G = input.next();
if (G.startsWith("x")) {
for (int g = 0; g < 7; g++) {
System.out.println();
}
}
System.out.println("RALOF: Hey, you there...");
System.out.println("You're finally awake. You were trying to cross the border, right?");
System.out.println("Walked right into that imperial ambush, same as us, and the thief over there.");
System.out.println("Continue... (x)");
String H = input.next();
if (H.startsWith("x")) {
for (int h = 0; h < 7; h++) {
System.out.println();
}
}
System.out.println("LOKIR: Damn you Stormcloaks. Skyrim was fine until you came along. Empire was nice and lazy...");
System.out.println("If they hadnt been looking for you, I could've stolen that horse and been halfway to Hammerfell.");
System.out.println("You there. You and me -- we shouldnt be here. It's these Stormcloaks the Empire wants.");
System.out.println("Continue... (x)");
String I = input.next();
if (I.startsWith("x")) {
for (int i = 0; i < 7; i++) {
System.out.println();
}
}
System.out.println("RALOF: We're all brothers and sisters in binds now, thief.");
System.out.println("Continue... (x)");
String J = input.next();
if (J.startsWith("x")) {
for (int j = 0; j < 7; j++) {
System.out.println();
}
}
System.out.println("You notice the man driving the cart to your left and that he is dressed in imperial armour.");
System.out.println("He notices you eyeing him and hears Ralof and Lokir talking.");
System.out.println("'Shut up back there!' he says");
//mountains();
//wagonWithSnow();
System.out.println("Snow continues to fall as the cart you have awoken on makes its way through the snowy mountain passes...");
System.out.println("Continue... (Press Any Key)");
String K = input.next();
if (K.startsWith("x")) {
for (int k = 0; k < 7; k++) {
System.out.println();
}
}
System.out.println("[Lokir looks at the gagged man.]");
System.out.println("LOKIR: And what's wrong with him?");
System.out.println("Continue... (x)");
String L = input.next();
if (L.startsWith("x")) {
for (int l = 0; l < 7; l++) {
System.out.println();
}
}
System.out.println("RALOF: Watch your tongue! You're speaking to Ulfric Stormcloak, the true High King.");
System.out.println("LOKIR: Ulfric? The Jarl of Windhelm? You're the leader of the rebellion. But if they captured you...");
System.out.println("Oh gods, where are they taking us?");
System.out.println("RALOF: I don't know where we're going, but Sovngarde awaits.");
System.out.println("LOKIR: No, this can't be happening. This isn't happening.");
System.out.println("Continue... (x)");
String M = input.next();
if (M.startsWith("x")) {
for (int m = 0; m < 7; m++) {
System.out.println();
}
}
System.out.println("RALOF: Hey, what village are you from, horse thief?");
System.out.println("LOKIR: Why do you care?");
System.out.println("RALOF: A Nord's last thoughts should be of home.");
System.out.println("LOKIR: Rorikstead. I'm...I'm from Rorikstead.");
System.out.println("Continue... (x)");
String N = input.next();
if (N.startsWith("x")) {
for (int n = 0; n < 7; n++) {
System.out.println();
}
}
System.out.println("As the cart makes its way through the snowy mountain passes, they arrive at the gates of Helgan.\n");
//HelganGate();
System.out.println("Continue... (x)");
String R = input.next();
if (R.startsWith("x")) {
for (int r = 0; r < 7; r++) {
System.out.println();
}
}
System.out.println("A soldier calls out to the lead wagon,");
System.out.println("Imperial Soldier: General Tullius, sir! The headsman is waiting!");
System.out.println("General Tullius: Good. Let's get this over with.");
System.out.println("Continue... (x)");
String O = input.next();
if (O.startsWith("x")) {
for (int o = 0; o < 7; o++) {
System.out.println();
}
}
System.out.println("LOKIR: Shor, Mara, Dibella, Kynareth, Akatosh. Divines, please help me!");
System.out.println("RALOF: Look at him, General Tullius the Military Governor. And it looks like the");
System.out.println("Thalmor are with him. Damn elves. I bet they had something to do with this.");
System.out.println("RALOF: This is Helgen. I used to be sweet on a girl from here. Wonder if Vilod");
System.out.println("is still making that mead with juniper berries mixed in. Funny...when I");
System.out.println("was a boy, Imperial walls and towers used to make me feel so safe.");
System.out.println("Continue... (x)");
String P = input.next();
if (P.startsWith("x")) {
for (int p = 0; p < 7; p++) {
System.out.println();
}
}
System.out.println("[A man and son watch the prisoners pull into town.]");
System.out.println("HAMING (little boy): Who are they, daddy? Where are they going?");
System.out.println("TOROLF (father): You need to go inside, little cub.");
System.out.println("HAMING (little boy): Why? I want to watch the soldiers.");
System.out.println("TOROLF (father): Inside the house. Now.");
System.out.println("Continue... (x)");
String Q = input.next();
if (Q.startsWith("x")) {
for (int q = 0; q < 7; q++) {
System.out.println();
}
}
System.out.println("[The wagon stops near the chopping block.]");
System.out.println("IMPERIAL SOLDIER: \"Whoa...WHOA...whoa\" he says to the horses pulling the carriage");
System.out.println("LOKIR: Why are they stopping?");
System.out.println("RALOF: Why do you think? End of the line. Let's go. Shouldn't keep the gods waiting for us.");
System.out.println("LOKIR: No! Wait! We're not rebels!");
System.out.println("RALOF: Face your death with some courage, thief.");
System.out.println("Continue... (x)");
String V = input.next();
if (V.startsWith("x")) {
for (int v = 0; v < 7; v++) {
System.out.println();
}
}
System.out.println("[Under the Imperials' watchful eye, the prisoners start jumping out.]");
System.out.println("LOKIR: You've got to tell them! We weren't with you! This is a mistake!");
System.out.println("IMPERIAL CAPTAIN: Step toward the block when we call your name. One at a time!");
System.out.println("RALOF: Empire loves their damn lists.");
System.out.println("Continue... (x)");
String S = input.next();
if (S.startsWith("x")) {
for (int s = 0; s < 7; s++) {
System.out.println();
}
}
System.out.println("HADVAR: Ulfric Stormcloak. Jarl of Windhelm.");
System.out.println("RALOF: It has been an honor, Jarl Ulfric!");
System.out.println("Continue... (x)");
String T = input.next();
if (T.startsWith("x")) {
for (int t = 0; t < 7; t++) {
System.out.println();
}
}
System.out.println("HADVAR: Ralof of Riverwood. Lokir of Rorikstead.");
System.out.println("LOKIR: No, I'm not a rebel! You can't do this!");
System.out.println("[He makes a break for it.]");
System.out.println("IMPERIAL CAPTAIN: Halt!");
System.out.println("LOKIR: You're not going to kill me!");
System.out.println("IMPERIAL CAPTAIN: Archers!");
System.out.println("[Lokir is downed with one bowshot.]");
//archer();
System.out.println("IMPERIAL CAPTAIN: Anyone else feel like running?");
System.out.println("[One of the guards looks back over to you with a sad expression on his face.]");
System.out.println("HADVAR: Wait, you there. Step forward. Who are you?");
}
}
答案 0 :(得分：3)
问题的一些修整：
do {
next = input.next();
while (!next.startsWith("y") || !next.startsWith("n"));
最简单的解释是从布尔代数的角度来看它：
not(x) or not(y) = not(x and y)
当我们用x和y代替您的字符串条件时：
not(next.startsWith("y")) or not(next.startsWith("n"))
等于
not(next.startsWith("y") and next.startsWith("n"))
由于字符串永远不能以“ n”和“ y”开头，因此该语句始终为假，因此其否定始终为真。这就是为什么它是一个无休止的循环。
解决方案：做到
do {
next = input.next();
while (!next.startsWith("y") && !next.startsWith("n"));
我想这就是您想要的。
答案 1 :(得分：0)
这两者不能一次都为假
!next.startsWith("y") || !next.startsWith("n")
假设输入为y
!true || !false
false || true
true
然后循环再次重复。
也许是您要寻找的行为。
!next.startsWith("y") && !next.startsWith("n")