HOWTO · Java
在 Java 中打印金字塔形的星星
本教程演示如何在 Java 中打印金字塔星星。
基于模式的练习是学习 Java 中嵌套循环的好方法，打印金字塔结构是进行这些练习的最佳示例。
本教程演示如何在 Java 中打印不同的星形金字塔。
用 Java 打印星星金字塔
按照以下步骤在 Java 中打印星形金字塔。
-
决定行数。
-
外循环的第一次迭代将打印金字塔图案的第一行。
-
外部循环内部将有两个循环：第一个循环打印每一行的空格，另一个循环打印金字塔每一行的星星。
让我们实现这些步骤：
package delftstack;
import java.util.*;
public class Pyramid_Stars {
public static void main(String[] args) {
int pyramid_rows;
int x;
int pyramid_spaces;
int star_count;
Scanner enter_rows = new Scanner(System.in);
System.out.print("Enter the number of rows of pyramid: ");
pyramid_rows = enter_rows.nextInt();
// This loop will print one row in every iteration
for (x = 0; x < pyramid_rows; x++) {
// this loop will print the spaces
for (pyramid_spaces = x; pyramid_spaces < pyramid_rows; pyramid_spaces++) {
System.out.print(" ");
}
// this loop will print the stars
for (star_count = 0; star_count < (x + 1); star_count++) {
System.out.print("* ");
}
System.out.print("\n");
}
}
}
上面的代码将要求用户输入金字塔的行数并相应地打印行。
输出：
Enter the number of rows of pyramid: 7
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
在 Java 中打印星的倒金字塔
现在，让我们尝试打印一个倒金字塔形的星星。我们可以通过反转上面代码中描述的过程来打印倒金字塔。
例子：
package delftstack;
import java.util.*;
public class Pyramid_Stars {
public static void main(String[] args) {
int pyramid_rows;
int x;
int pyramid_spaces;
int star_count;
Scanner enter_rows = new Scanner(System.in);
System.out.print("Enter the number of rows of pyramid: ");
pyramid_rows = enter_rows.nextInt();
// This loop will print one row in every iteration
for (x = 0; x < pyramid_rows; x++) {
for (pyramid_spaces = 0; pyramid_spaces < x; pyramid_spaces++) {
System.out.print(" ");
}
for (star_count = x; star_count < pyramid_rows; star_count++) {
System.out.print("* ");
}
System.out.print("\n");
}
}
}
此代码将通过从用户那里获取输入行来打印倒金字塔。
输出：
Enter the number of rows of pyramid: 7
* * * * * * *
* * * * * *
* * * * *
* * * *
* * *
* *
*
在 Java 中同时打印原始和倒置的双星金字塔
双星金字塔将创建一个类似钻石的形状。
例子：
package delftstack;
import java.util.*;
public class Pyramid_Stars {
public static void main(String[] args) {
int pyramid_rows;
int x;
int pyramid_spaces;
int star_count;
Scanner enter_rows = new Scanner(System.in);
System.out.print("Enter the number of rows of pyramid: ");
pyramid_rows = enter_rows.nextInt();
// Loops for the first pyramid
for (x = 0; x < pyramid_rows; x++) {
for (pyramid_spaces = x; pyramid_spaces < pyramid_rows; pyramid_spaces++) {
System.out.print(" ");
}
for (star_count = 0; star_count < (x + 1); star_count++) {
System.out.print("* ");
}
System.out.print("\n");
}
// Loops for the inverted pyramid
for (x = pyramid_rows; x > 0; x = (x - 1)) {
for (pyramid_spaces = pyramid_rows; pyramid_spaces >= (x - 1); pyramid_spaces--) {
System.out.print(" ");
}
for (star_count = (x - 1); star_count > 0; star_count--) {
System.out.print("* ");
}
System.out.print("\n");
}
}
}
输出：
Enter the number of rows of pyramid: 7
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
* * * * * *
* * * * *
* * * *
* * *
* *
*
在 Java 中打印半个金字塔的星星
要打印半金字塔，我们只需要两个循环。
例子：
package delftstack;
import java.util.*;
public class Pyramid_Stars {
public static void main(String[] args) {
int pyramid_rows;
int x;
int star_count;
Scanner enter_rows = new Scanner(System.in);
System.out.print("Enter the number of rows of pyramid: ");
pyramid_rows = enter_rows.nextInt();
// This loop will print one row in every iteration
for (x = 0; x < pyramid_rows; x++) {
for (star_count = 0; star_count <= x; star_count++) {
System.out.print("* ");
}
System.out.print("\n");
}
}
}
输出：
Enter the number of rows of pyramid: 7
*
* *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
在 Java 中打印倒置的半金字塔形的星星
通过更改上面代码中的第二个循环，我们可以在 Java 中打印倒置的半金字塔。
例子：
package delftstack;
import java.util.*;
public class Pyramid_Stars {
public static void main(String[] args) {
int pyramid_rows;
int x;
int star_count;
Scanner enter_rows = new Scanner(System.in);
System.out.print("Enter the number of rows of pyramid: ");
pyramid_rows = enter_rows.nextInt();
// This loop will print one row in every iteration
for (x = 0; x < pyramid_rows; x++) {
for (star_count = x; star_count < pyramid_rows; star_count++) {
System.out.print("* ");
}
System.out.print("\n");
}
}
}
输出：
Enter the number of rows of pyramid: 7
* * * * * * *
* * * * * *
* * * * *
* * * *
* * *
* *
*
