问题描述
我一直在尝试用 Java 完成这项工作。而且这画起来很复杂，至少对我来说是这样。
Q1 编写一个简单的 Java 程序，打印楼梯或图形，如下所示：
+---+
| |
+---+---+
| | |
+---+---+---+
| | | |
+---+---+---+---+
| | | | |
+---+---+---+---+---+
| | | | | |
+---+---+---+---+---+
public class DrawStairs {
public static final int HEIGHT = 5;
public static final int TOTALHEIGHT = HEIGHT * 5;
public static void main(String[] args) {
//Main Outer Loop
for (int i = 1; i <= HEIGHT; i++) {
//Loop for the spaces before,then print the head
for (int j = 1; j <= TOTALHEIGHT + (i * (-5)); j++) {
System.out.print(" ");
}
printTop();
//Loop for spaces after,then print asterisk
for (int j = 1; j <= (i - 1); j++) {
System.out.print("---+");
}
System.out.println(" ");
//Loop for the spaces before,then print the body
for (int j = 1; j <= TOTALHEIGHT + (i * (-5)); j++) {
System.out.print(" ");
}
printMiddle();
//Loop for spaces after,then print asterisk
for (int j = 1; j <= (i - 1) * 5; j++) {
System.out.print(" ");
}
//Loop for spaces before,then print the legs
for (int j = 1; j <= TOTALHEIGHT + (i * (-5)); j++) {
System.out.print(" ");
}
printBottom();
//Loop for spaces after,then print asterisk
for (int j = HEIGHT; j <= 0; --j) {
System.out.print("---+");
}
System.out.println("|");
}
// for loop for printing the floor of asterisks
for (int i = 1; i <= HEIGHT; i++) {
System.out.print("+---+");
}
}
public static void printTop() {
System.out.print("+---+");
}
public static void printMiddle() {
System.out.print("| |");
}
public static void printBottom() {
// System.out.print("+---+");
}
}
这就是它的作用。
+---+
| | |
+---+---+
| | |
+---+---+---+
| | |
+---+---+---+---+
| | |
+---+---+---+---+---+
| | |
+---++---++---++---++---+
任何人都可以帮助我并指导我使用我的代码吗？我希望有人能告诉我出了什么问题以及应该更改什么。
解决方法
这是我对问题的解决方案。谢谢你的拼图;)
public class Staircase {
public static final int SIZE = 5;
public static final int STAIR_WIDTH = 5;
public static final String TREAD = "-";
public static final String RISER = "|";
public static final String NOSING = "+";
public static final String HOLLOW = " ";
public static void main(String[] args)
{
StringBuilder step = new StringBuilder();
for (int i = 0; i < (STAIR_WIDTH - 2); ++i) { step.append(TREAD); }
StringBuilder hollow = new StringBuilder();
for (int i = 0; i < (STAIR_WIDTH - 2); ++i) { hollow.append(HOLLOW); }
StringBuilder tread = new StringBuilder();
for (int i = 0; i < SIZE; ++i) { tread.append(NOSING + step); }
tread.append(NOSING);
StringBuilder riser = new StringBuilder();
for (int i = 0; i < SIZE; ++i) { riser.append(RISER + hollow); }
riser.append(RISER);
for (int i = 0; i < SIZE; ++i) {
int offset = tread.length() - (((STAIR_WIDTH - 1) * i) + STAIR_WIDTH);
printSpaces(offset);
System.out.println(tread.substring(offset));
printSpaces(offset);
System.out.println(riser.substring(offset));
}
System.out.println(tread);
}
public static void printSpaces(int count)
{
for (int i = 0; i < count; ++i)
System.out.print(" ");
}
}
public class Staircase {
// You can change the height to any number and check
public static final int HEIGHT = 5;
public static void main(String[] args) {
Staircase stairs = new Staircase();
for (int j = 0; j < HEIGHT; j++) {
stairs.printSpace(j);
stairs.printTop(j);
stairs.printSpace(j);
stairs.printMiddle(j);
}
stairs.printTop(HEIGHT-1); // added for bottom line stairs
}
public void printSpace(int j) {
for (int i = j; i < HEIGHT - 1; i++) {
System.out.print(" ");
}
}
public void printTop(int j) {
for (int k = 0; k <= j; k++) {
System.out.print("+--");
}
System.out.print("+");
System.out.println("");
}
public void printMiddle(int j) {
for (int k = 0; k <= j; k++) {
System.out.print("| ");
}
System.out.print("|");
System.out.println("");
}
}
另一个答案，所以你可以看到很多很多方法可以解决这个问题。这个使用单个绘制循环，并避免使用常量：
public static void drawStaircase(int steps,String stepTop,String stepLeft,String stepEmpty) {
String endOfTopStep = stepTop.substring(0,1); // "+---" => "+"
String endOfMidStep = stepLeft.substring(0,1); // "|---" => "|"
for (int row=0; row<steps;row++) {
// paint a top-of-step row
for (int col=0; col<steps; col++) {
boolean isEmpty = row+col+1 < steps;
System.out.print(isEmpty ? stepEmpty : stepTop);
}
System.out.println(endOfTopStep);
// paint a middle-of-step row
for (int col=0; col<steps; col++) {
boolean isEmpty = row+col+1 < steps;
System.out.print(isEmpty ? stepEmpty : stepLeft);
}
System.out.println(endOfMidStep);
}
// paint bottom border
for (int col=0; col<steps; col++) {
System.out.print(stepTop);
}
System.out.println(endOfTopStep);
}
public static void main(String ...args) {
drawStaircase(4,"+---","| "," ");
}
我创建此代码是为了说明如何解决问题并逐步分解，直到您可以解决每个步骤。
这是我的许多测试结果之一的结果。
+---+
| |
+---+---+
| | |
+---+---+---+
| | | |
+---+---+---+---+
| | | | |
+---+---+---+---+---+
| | | | | |
+---+---+---+---+---+
我做的第一件事是创建一个方法来生成一个空白段。我使用 StringBuilder 类可以更轻松地构建线段并将它们连接起来。
一旦我开始工作，我就创建了创建台阶（平台）和托梁的方法。
接下来，我创建了一个方法来创建一行输出。
最后，我创建了一个方法来创建整个楼梯。
这是完整的可运行代码。它可能不是最高效的代码，但我希望它是最容易理解的代码之一。
public class Staircase {
public static void main(String[] args) {
Staircase sc = new Staircase();
System.out.println(sc.createStaircase(5));
}
public String createStaircase(int steps) {
StringBuilder builder = new StringBuilder();
int blankSteps = 0;
String step = createStepSegment();
String joist = createJoistSegment();
for (int i = 1; i <= steps; i++) {
blankSteps = Math.max(0,steps - i);
builder.append(createLine(step,steps,blankSteps));
builder.append(createLine(joist,blankSteps));
}
builder.append(createLine(step,blankSteps));
return builder.toString();
}
private StringBuilder createLine(String string,int steps,int blankSteps) {
StringBuilder builder = new StringBuilder();
int width = string.length() * blankSteps;
builder.append(createBlankSegment(width));
int boxSteps = steps - blankSteps;
for (int i = 0; i < boxSteps; i++) {
builder.append(string);
}
builder.append(string.charAt(0));
builder.append(System.lineSeparator());
return builder;
}
private String createStepSegment() {
return "+---";
}
private String createJoistSegment() {
return "| ";
}
private StringBuilder createBlankSegment(int length) {
StringBuilder builder = new StringBuilder();
for (int i = 0; i < length; i++) {
builder.append(" ");
}
return builder;
}
}
您可以使用 streams 构建楼梯：
int m = 5;
String[] arr = IntStream.range(0,m).mapToObj(i -> {
String[] arr1 = new String[m];
String[] arr2 = new String[m];
String[] arr3 = new String[m];
IntStream.range(0,m).forEach(j -> {
if (i + j >= m - 1) {
if (j == m - 1) {
arr1[j] = "+---+";
arr2[j] = "| |";
arr3[j] = "+---+";
} else {
arr1[j] = "+---";
arr2[j] = "| ";
arr3[j] = "+---";
}
} else {
arr1[j] = " ";
arr2[j] = " ";
}
});
if (i == m - 1) {
return Stream.of(arr1,arr2,arr3);
} else {
return Stream.of(arr1,arr2);
}
}).flatMap(Function.identity())
.map(row -> String.join("",row))
.toArray(String[]::new);
// output
Arrays.stream(arr).forEach(System.out::println);
+---+
| |
+---+---+
| | |
+---+---+---+
| | | |
+---+---+---+---+
| | | | |
+---+---+---+---+---+
| | | | | |
+---+---+---+---+---+
您可以将楼梯表示为 zeros 和 ones 的二维数组，如下所示：
[0,1]
[0,1,1]
[1,1]
然后你可以将这个数组的非空单元格表示为一个几乎正方形，由两行组成：一行带有上边框，一行带有左边框。空单元格只是两行相同长度的空格。
+---
|
然后就可以将每一行的单元格拼接成一行，并逐行输出。结果由两部分组成：带有右边框和下边框的二维数组的行：
n=6
+---+
| |
+---+---+
| | |
+---+---+---+
| | | |
+---+---+---+---+
| | | | |
+---+---+---+---+---+
| | | | | |
+---+---+---+---+---+---+
| | | | | | |
+---+---+---+---+---+---+
int n = 6;
// 2d array of zeros and ones
int[][] field = IntStream.range(0,n)
.mapToObj(i -> IntStream.range(0,n)
.map(j -> i + j < n - 1 ? 0 : 1)
.toArray())
.toArray(int[][]::new);
String[] staircase = Stream.concat(
// rows of a 2d array with a right border
Arrays.stream(field)
.map(row -> IntStream.range(0,n)
.mapToObj(i -> new String[]{
// upper row of square with an upper border
row[i] == 0 ? " " : "+---"
// add a right border to the last element
+ (i < n - 1 ? "" : "+"),// lower row of square with a left border
row[i] == 0 ? " " : "| "
// add a right border to the last element
+ (i < n - 1 ? "" : "|")})
// reduce Stream<String[]> to a single array String[]
.reduce((arr1,arr2) -> IntStream.range(0,2)
.mapToObj(j -> arr1[j] + arr2[j])
.toArray(String[]::new))
.orElse(new String[]{}))
.flatMap(Arrays::stream),// lower border row
Stream.of(IntStream.range(0,n)
.mapToObj(i -> "+---" + (i < n - 1 ? "" : "+"))
.collect(Collectors.joining())))
.toArray(String[]::new);
// output
System.out.println("n=" + n);
Arrays.stream(staircase).forEach(System.out::println);