java - 在Java中将*s打印为三角形？

Question

我在 Java 课程中的任务是制作 3 个三角形。一个左对齐，一个右对齐，一个居中。我必须为什么类型的三角形制作一个菜单，然后输入需要多少行。三角形必须看起来像这样

*
**
***
****


   *
  **
 ***
****


  *
 ***
*****

到目前为止，我能够做左对齐的三角形，但我似乎无法得到另外两个。我尝试使用谷歌搜索，但没有任何结果。任何人都可以帮忙吗？到目前为止我有这个。

import java.util.*;
public class Prog673A
{
    public static void leftTriangle()
    {
        Scanner input = new Scanner (System.in);
        System.out.print("How many rows: ");
        int rows = input.nextInt();
        for (int x = 1; x <= rows; x++)
        {
            for (int i = 1; i <= x; i++)
            {
                System.out.print("*");
            }
            System.out.println("");
        }
    }
    public static void rightTriangle()
    {
        Scanner input = new Scanner (System.in);
        System.out.print("How many rows: ");
        int rows = input.nextInt();
        for (int x = 1; x <= rows; x++)
        {
            for (int i = 1; i >= x; i--)
            {
                System.out.print(" ");
            }
            System.out.println("*");
        }
    }
    public static void centerTriangle()
    {

    }
    public static void main (String args [])
    {
        Scanner input = new Scanner (System.in);
        System.out.println("Types of Triangles");
        System.out.println("\t1. Left");
        System.out.println("\t2. Right");
        System.out.println("\t3. Center");
        System.out.print("Enter a number: ");
        int menu = input.nextInt();
        if (menu == 1)
            leftTriangle();
        if (menu == 2)
            rightTriangle();
        if (menu == 3)
            centerTriangle();
    }
}

样本输出：

Types of Triangles
1.  Left
2.  Right
3.  Center
Enter a number (1-3):  3
How many rows?: 6

     *
    ***
   *****
  *******
 *********
***********

score 15 · Accepted Answer

提示：对于每一行，您需要先打印一些空格，然后再打印一些星号。空格数应每行减少一个，而星数应增加。

对于居中的输出，将每行的星数增加两个。

score 6 · Accepted Answer

Ilmari Karonen 有很好的建议，我想概括一下。一般来说，在你问“我怎样才能让电脑来做这件事？”之前。问“我该怎么做？”

所以，如果有人给你一个空的 Word 文档并要求你创建三角形，你会怎么做呢？无论您想出什么解决方案，通常都不难将其翻译成 Java（或任何其他编程语言）。它可能不是最好的解决方案，但（希望如此！）它会起作用，它可能会为您指明更好的解决方案。

例如，也许你会说你要输入基数，然后上一行，然后输入下一个最高的行，等等。这表明你可以在 Java 中做同样的事情——创建一个字符串列表，从底部到顶部，然后将它们反转。这可能表明您可以按相反的顺序创建它们，然后不必颠倒它们。然后这可能表明您不再需要该列表，因为您只需按照相同的顺序创建和打印它们——此时您基本上已经提出了 Ilmari Karonen 的建议。

或者，也许你会想出另一种方法——也许你会更直接地想出 Ilmari Karonen 的想法。无论如何，它应该可以帮助您解决这个问题和许多其他问题。

score 2 · Accepted Answer

这是正常三角形：

for (int i = 0; i < 5; i++) {
    for (int j = 5; j > i; j--) {
        System.out.print(" ");
    }
    for (int k = 1; k <= i + 1; k++) {
        System.out.print(" *");
    }
    System.out.print("\n");
}

输出：

      *
     * *
    * * *
   * * * *
  * * * * *

这是左三角形，只是在打印前删除了空间*：

for (int i = 0; i < 5; i++) {
    for (int j = 5; j > i; j--) {
        System.out.print(" ");
    }
    for (int k = 1; k <= i + 1; k++) {
        System.out.print("*");
    }
    System.out.print("\n");
}

输出：

     *
    **
   ***
  ****
 *****

score 2 · Accepted Answer

package apple;

public class Triangle {
    private static final int row = 3;

    public static void main(String... strings) {
        printLeftTriangle();
        System.out.println();
        printRightTriangle();
        System.out.println();
        printTriangle();
    }

    // Pattern will be
    // *
    // **
    // ***
    public static void printLeftTriangle() {
        for (int y = 1; y <= row; y++) {
            for (int x = 1; x <= y; x++)
                System.out.print("*");
            System.out.println();
        }
    }

    // Pattern will be
    //   *
    //  **
    // ***
    public static void printRightTriangle() {
        for (int y = 1; y <= row; y++) {
            for (int space = row; space > y; space--)
                System.out.print(" ");
            for (int x = 1; x <= y; x++)
                System.out.print("*");
            System.out.println();
        }
    }

    // Pattern will be
    //   *
    //  ***
    // *****
    public static void printTriangle() {
        for (int y = 1, star = 1; y <= row; y++, star += 2) {
            for (int space = row; space > y; space--)
                System.out.print(" ");
            for (int x = 1; x <= star; x++)
                System.out.print("*");
            System.out.println();
        }
    }
}

score 2 · Accepted Answer

左对齐三角形- * **

from above pattern we come to know that-
1)we need to print pattern containing n rows (for above pattern n is 4).
2)each  row contains star and no of stars i each row is incremented by 1.
So for Left alinged triangle we need to use 2 for loop.
1st "for loop" for printing n row.
2nd  "for loop for printing stars in each rows. 


 Code for  Left alinged triangle-

 public static void leftTriangle()
{
       /// here  no of rows is 4
 for (int a=1;a<=4;a++)// for loop for row
 {   
 for (int b=1;b<=a;b++)for loop for column
 {
 System.out.print("*");
 }

System.out.println();}
}

直角三角形- *
**

from above pattern we come to know that-
1)we need to print pattern containing n rows (for above pattern n is 4).
 2)In each  row we need to print spaces followed by a star & no of spaces            in each row is decremented by 1.
 So for Right alinged triangle we need to use 3 for loop.
 1st "for loop" for printing n row.
 2nd  "for loop for printing spaces.
 3rd "for loop" for printing stars.

Code for Right alinged triangle -

public void rightTriangle()
{
    // here 1st print space and then print star
  for (int a=1;a<=4;a++)// for loop for row
 { 
 for (int c =3;c>=a;c--)// for loop fr space
 {  
 System.out.print(" ");
 }
 for (int d=1;d<=a;d++)// for loop for column
 { 
 System.out.print("*");   
 }
 System.out.println(); 
 }
 }

中心三角形- *
* *

从上面的模式我们知道 - 1）我们需要打印包含 n 行的模式（因为上面的模式 n 是 4）。2）最初在每一行中，我们需要打印空格，后跟一个星号，然后再打印一个空格。开始时每行中的空格数减 1。因此对于直角三角形，我们需要使用 3 for 循环。第一个用于打印 n 行的“for 循环”。第二个“for循环”用于打印空间。第三个“for循环”用于打印星星。

中心三角形的代码-

public  void centerTriangle()
{   
for (int a=1;a<=4;a++)// for lop for row
{   
for (int c =4;c>=a;c--)// for loop for space
{  
System.out.print(" ");
}
for (int b=1;b<=a;b++)// for loop for column
{
System.out.print("*"+" ");
}
System.out.println();}
}

打印所有 3 种模式的代码 - public class space4 { public static void leftTriangle() { /// 这里的行数是 4 for (int a=1;a<=4;a++)// for loop for row {
for ( int b=1;b<=a;b++)for 列循环 { System.out.print("*"); }

System.out.println();}
}

public static void rightTriangle()
{
    // here 1st print space and then print star
  for (int a=1;a<=4;a++)// for loop for row
 { 
 for (int c =3;c>=a;c--)// for loop for space
 {  
 System.out.print(" ");
 }
 for (int d=1;d<=a;d++)// for loop for column
 { 
 System.out.print("*");   
 }
 System.out.println(); 
 }
 }

public static void centerTriangle()
{   
for (int a=1;a<=4;a++)// for lop for row
{   
for (int c =4;c>=a;c--)// for loop for space
{  
System.out.print(" ");
}
for (int b=1;b<=a;b++)// for loop for column
{
System.out.print("*"+" ");
}
System.out.println();}
}
public static void main (String args [])
{
space4 s=new space4();
s.leftTriangle();
s.rightTriangle();
s.centerTriangle();
}
}

score 1 · Accepted Answer

1) 法线三角形

package test1;


 class Test1 {

     public static void main(String args[])
     {
         int n=5;
     for(int i=0;i<n;i++)
     {

         for(int j=0;j<=n-i;j++)
         {

             System.out.print(" ");
         }

         for(int k=0;k<=2*i;k++)
         {
         System.out.print("*");
         }

         System.out.println("\n");

     }

     }

2）直角三角形

package test1;


 class Test1 {

     public static void main(String args[])
     {
         int n=5;
     for(int i=0;i<n;i++)
     {

         for(int j=0;j<=n-i;j++)
         {

             System.out.print(" ");
         }

         for(int k=0;k<=i;k++)
         {
         System.out.print("*");
         }

         System.out.println("\n");

     }

     }


}

     }

3) 左角三角形

package test1;


 class Test1 {

     public static void main(String args[])
     {
         int n=5;
     for(int i=0;i<n;i++)
     {

         for(int j=0;j<=i;j++)
         {

             System.out.print("*");
         }

         System.out.println("\n");

     }

     }


}

score 1 · Accepted Answer

我知道这已经很晚了，但我想分享我的解决方案。

public static void main(String[] args) {
    String whatToPrint = "aword";
    int strLen = whatToPrint.length(); //var used for auto adjusting the padding
    int floors = 8;
    for (int f = 1, h = strLen * floors; f < floors * 2; f += 2, h -= strLen) {
        for (int k = 1; k < h; k++) {
                System.out.print(" ");//padding
            }
        for (int g = 0; g < f; g++) {
            System.out.print(whatToPrint);
        }
        System.out.println();
    }
}

三角形左侧的空格会根据您要打印的字符或单词自动调整。

如果whatToPrint = "x"它floors = 3会打印

x xxx xxxxx 如果没有自动调整空间，它看起来像这样（whatToPrint = "xxx"相同的楼层数）

xxx xxxxxxxxx xxxxxxxxxxxxxxx

所以我添加了一个简单的代码，这样它就不会发生。

对于左半三角形，只需更改strLen * floorstostrLen * (floors * 2)和f +=2to f++。

对于右半三角形，只需删除此循环for (int k = 1; k < h; k++)或更改h为0，如果您选择删除它，请不要删除System.out.print(" ");.

score 0 · Accepted Answer

import java.util.Scanner;

public class A {

    public void triagle_center(int max){//max means maximum star having
        int n=max/2;
        for(int m=0;m<((2*n)-1);m++){//for upper star
            System.out.print(" ");
        }
        System.out.println("*");

        for(int j=1;j<=n;j++){
            for(int i=1;i<=n-j; i++){
                System.out.print("  ");
            }
            for(int k=1;k<=2*j;k++){
            System.out.print("* ");
            }

            System.out.println();
        }


    }

    public void triagle_right(int max){
        for(int j=1;j<=max;j++){
            for(int i=1;i<=j; i++){
                System.out.print("* ");
            }

            System.out.println();
        }
    }

    public void triagle_left(int max){
        for(int j=1;j<=max;j++){
            for(int i=1;i<=max-j; i++){
                System.out.print("  ");
            }
            for(int k=1;k<=j; k++){
                System.out.print("* ");
            }

            System.out.println();
        }
    }

    public static void main(String args[]){
        A a=new A();
        Scanner input = new Scanner (System.in);
        System.out.println("Types of Triangles");
        System.out.println("\t1. Left");
        System.out.println("\t2. Right");
        System.out.println("\t3. Center");
        System.out.print("Enter a number: ");
        int menu = input.nextInt();
        Scanner input1 = new Scanner (System.in);
        System.out.print("maximum Stars in last row: ");
        int row = input1.nextInt();
        if (menu == 1)
            a.triagle_left(row);
        if (menu == 2)
            a.triagle_right(row);
        if (menu == 3)
            a.triagle_center(row);
    }
}

score 0 · Accepted Answer

对于三角形来说，你需要三个循环来代替两个循环，一个外循环来迭代主循环内的两个并行循环第一个循环打印减少循环数第二个循环打印增加没有' '我可以也给出确切的逻辑，但如果你首先尝试集中在每行中需要多少个空格和多少个' ''将符号的数量与循环迭代的行数联系起来，你就完成了......如果更麻烦，请告诉我，我也会用逻辑和代码解释

score 0 · Accepted Answer

对于直角三角形，对于每一行：

首先：您需要打印从 0 到rowNumber - 1 - i.
第二：您需要\*从rowNumber - 1 - ito打印rowNumber。

注意： i是从 0 到的行索引，rowNumber是rowNumber行数。

对于中心三角形：它看起来像“直角三角形”加上 \*根据行索引添加（例如：在第一行中您将不添加任何内容，因为索引为 0 ，在第二行中您将添加一个 ' * '，等等上）。

score 0 · Accepted Answer

这将以三角形打印星星：

`   
public class printstar{
public static void main (String args[]){
int m = 0;
for(int i=1;i<=4;i++){
for(int j=1;j<=4-i;j++){
System.out.print("");}

for (int n=0;n<=i+m;n++){
if (n%2==0){
System.out.print("*");}
else {System.out.print(" ");}
}
m = m+1;
System.out.println("");
}
}
}'

阅读和理解这应该有助于您下次设计逻辑。

score 0 · Accepted Answer

找到以下内容，它将帮助您打印完整的三角形。

package com.raju.arrays;

公共类 CompleteTringe {

public static void main(String[] args) {
    int nuberOfRows = 10;
      for(int row = 0; row<nuberOfRows;row++){

          for(int leftspace =0;leftspace<(nuberOfRows-row);leftspace++){
              System.out.print(" ");
          }
          for(int star = 0;star<2*row+1;star++){
              System.out.print("*");
          }
          for(int rightSpace =0;rightSpace<(nuberOfRows-row);rightSpace++){
              System.out.print(" ");
          }
          System.out.println("");
      }

}

}

          *          
     ***         
    *****        
   *******       
  *********      
 ***********     
*************

score 0 · Accepted Answer

目标输出：

      *
     ***
    *****

执行：

for (int i = 5; i >= 3; i--)
    for (int a = 1; a <= i; a++)
    {   
        System.out.print(" ");
    }

    for (int j = 10; j/2>=i; j--)
    {
        System.out.print("*");
    }
    System.out.println("");
}

score 0 · Accepted Answer

public static void main(String[] args) {

    System.out.print("Enter the number: ");
    Scanner userInput = new Scanner(System.in);
    int myNum = userInput.nextInt();
    userInput.close();

    System.out.println("Centered Triange");
    for (int i = 1; i <= myNum; i+=1) {//This tells how many lines to print (height)

        for (int k = 0; k < (myNum-i); k+=1) {//Prints spaces before the '*'
            System.out.print(" ");
        }

        for (int j = 0; j < i; j++) { //Prints a " " followed by '*'.   
            System.out.print(" *");
        }

        System.out.println(""); //Next Line     
    }

    System.out.println("Left Triange");
    for (int i = 1; i <= myNum; i+=1) {//This tells how many lines to print (height)

        for (int j = 0; j < i; j++) { //Prints the '*' first in each line then spaces.  
            System.out.print("* ");
        }

        System.out.println(""); //Next Line         
    }

    System.out.println("Right Triange");
    for (int i = 1; i <= myNum; i+=1) {//This tells how many lines to print (height)

        for (int k = 0; k < (myNum-i); k+=1) {//Prints spaces before the '*'
            System.out.print("  ");
        }

        for (int j = 0; j < i; j+=1) { //Prints the " " first in each line then a "*".  
            System.out.print(" *");
        }

        System.out.println(""); //Next Line         
    }

}

score 0 · Accepted Answer

这是最简单的程序，它只需要 1 个 for 循环来打印三角形。这仅适用于中心三角形，但小的调整也可以使其适用于其他三角形 -

import java.io.DataInputStream;

public class Triangle {
    public static void main(String a[]) throws Exception{
        DataInputStream in = new DataInputStream(System.in);

        int n = Integer.parseInt(in.readLine());
        String b = new String(new char[n]).replaceAll("\0", " ");
        String s = "*";
        for(int i=1; i<=n; i++){
            System.out.print(b);
            System.out.println(s);
            s += "**";
            b = b.substring(0, n-i);
            System.out.println();
        }
    }
}

score 0 · Accepted Answer

对于中心三角形

      Scanner sc = new Scanner(System.in);
      int n=sc.nextInt();
      int b=(n-1)*2;  
      for(int i=1;i<=n;i++){
      int t= i;
      for(int k=1;k<=b;k++){
      System.out.print(" ");
       }
       if(i!=1){
        t=i*2-1;
       }
       for(int j=1;j<=t;j++){
       System.out.print("*");
       if(j!=t){
       System.out.print(" ");
       }
        }
        System.out.println();
            b=b-2;  
        }

输出：

            *
          * * *

score 0 · Accepted Answer

对于左对齐的直角三角形，您可以在 java 中尝试这个简单的代码：

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
      Scanner sc=new Scanner(System.in);
      int size=sc.nextInt();
       for(int i=0;i<size;i++){
           for(int k=1;k<size-i;k++){
                   System.out.print(" ");
               }
           for(int j=size;j>=size-i;j--){

               System.out.print("#");
           }
           System.out.println();
       }
    }
}

score 0 · Accepted Answer

    for(int i=1;i<=5;i++)
    {
        for(int j=5;j>=i;j--)
        {
            System.out.print(" ");
        }
        for(int j=1;j<=i;j++)
        {
            System.out.print("*");
        }

        for(int j=1;j<=i-1;j++)
        {
            System.out.print("*");
        }
        System.out.println("");
    }

 *
***

score 0 · Accepted Answer

public class Triangle {
    public static void main ( String arg[] ) {
        System.out.print("Enter Triangle Size : ");
        int num = 0;
        try {
            num = Integer.parseInt( read.readLine() );
        } catch(Exception Number) {
            System.out.println("Invalid Number!");
        }
        for(int i=1; i<=num; i++) {
            for(int j=1; j<num-(i-1); j++) {
                System.out.print(" ");
            }
            for(int k=1; k<=i; k++) {
                System.out.print("*");
                for(int k1=1; k1<k; k1+=k) {
                    System.out.print("*");
                }
            }
            System.out.println();
        }
    }
}

score -1 · Accepted Answer

(a)   (b)        (c)   (d)
* ********** ********** *
** ********* ********* **
*** ******** ******** ***
**** ******* ******* ****
***** ****** ****** *****
****** ***** ***** ******
******* **** **** *******
******** *** *** ********
********* ** ** *********
********** * * **********

int line;
int star;
System.out.println("Triangle a");
        for( line = 1; line <= 10; line++ )
        {
            for( star = 1; star <= line; star++ )
            {

                System.out.print( "*" );
            }
            System.out.println();
        }

 System.out.println("Triangle b");

          for( line = 1; line <= 10; line++ )
        {
            for( star = 1; star <= 10; star++ )
            {

        if(line<star)
                System.out.print( "*" );
                else
                  System.out.print(" ");
            }
            System.out.println();
        }

 System.out.println("Triangle c");

          for( line = 1; line <= 10; line++ )
        {
            for( star = 1; star <= 10; star++ )
            {

        if(line<=star)
                System.out.print( "*" );
                //else
                 // System.out.print(" ");
            }
            System.out.println();
        }

 System.out.println("Triangle d");

          for( line = 1; line <= 10; line++ )
        {
            for( star = 1; star <= 10; star++ )
            {

        if(line>10-star)
                System.out.print( "*" );
                else
                  System.out.print(" ");
            }
            System.out.println();
        }

score -1 · Accepted Answer

你可能也对此感兴趣

      Scanner sc = new Scanner(System.in);
      int n=sc.nextInt();
      int b=0;
      for(int i=n;i>=1;i--){
      if(i!=n){
      for(int k=1;k<=b;k++){
      System.out.print(" ");
        }
            }
       for(int j=i;j>=1;j--){
       System.out.print("*");
       if(i!=1){
       System.out.print(" ");
        }
            }
       System.out.println();
       b=b+2;
        }

输出:: 5

java - 在Java中将*s打印为三角形？

21 回答 21

Related

Reference