for循环执行打印出1-100的所有偶数

Posted 2023-05-13

for循环执行打印出1-100的所有偶数在html中用java语句

参考技术A for($i=2; $i<=100; $i++)
if($i%2 == 0)
echo "$i = ".$i." ";


echo '<br>';

用“for”循环在java中打印出菱形图案

【中文标题】用“for”循环在java中打印出菱形图案

【英文标题】：Printing out a rhombic pattern in java with "for" loop

【发布时间】：2015-11-05 13:29:03

【问题描述】：

我很难用 Java 进行学校练习。我们被要求打印出这个模式：

+++++++++++++++++++++++++++++++++++++++++++++
 +++++++  +++++++  +++++++  +++++++  +++++++ 
  +++++    +++++    +++++    +++++    +++++  
   +++      +++      +++      +++      +++   
    +        +        +        +        +    
   +++      +++      +++      +++      +++   
  +++++    +++++    +++++    +++++    +++++  
 +++++++  +++++++  +++++++  +++++++  +++++++ 
+++++++++++++++++++++++++++++++++++++++++++++
 +++++++  +++++++  +++++++  +++++++  +++++++ 
  +++++    +++++    +++++    +++++    +++++  
   +++      +++      +++      +++      +++   
    +        +        +        +        +    
   +++      +++      +++      +++      +++   
  +++++    +++++    +++++    +++++    +++++  
 +++++++  +++++++  +++++++  +++++++  +++++++ 
+++++++++++++++++++++++++++++++++++++++++++++
 +++++++  +++++++  +++++++  +++++++  +++++++ 
  +++++    +++++    +++++    +++++    +++++  
   +++      +++      +++      +++      +++   
    +        +        +        +        +    
   +++      +++      +++      +++      +++   
  +++++    +++++    +++++    +++++    +++++  
 +++++++  +++++++  +++++++  +++++++  +++++++ 
+++++++++++++++++++++++++++++++++++++++++++++

我可以做一个三角形或沙漏形状，但我不能让它水平重复。

这是我目前所拥有的：

int a = 9;
char b = '+';
char c = ' ';

int i_buffer = a;
int i_leer = 1;
for (int i = 0; i < a; i++) 
    for (int z = i_buffer; z > 0; z--)
        System.out.print(b);

    System.out.println();

    i_buffer = i_buffer - 2;
    if (i_buffer < 0)
        break;

    for (int z = i_leer++; z > 0; z--)
        System.out.print(c);

【问题讨论】：

循环重复println()之前的操作5次？

菱形是新金字塔。

大提示：由于这具有明显的水平和垂直周期性，请使用模运算符（％）。本质上，整个输出是一个具有一定数量的行和列的矩阵，每个元素是一个加号或一个空格。因此，归结为编写一个函数 f(row, col)，例如返回 1 表示 + 或 0 表示空格。

@tobias_k 我试过了，但它没有打印任何空格......它所做的只是很多加号。

@MarounMaroun 哈哈大笑

【参考方案1】：

这里有一个解决方案，可以根据需要在 x 和 y 维度上以每个尺寸创建此模式。实际发生的事情写成评论。

public static void main(String[] args) 
    test();


public static void test() 
    // Print it three times under each other, 5 times next to each other 
    // With a size of 9 plus
    printHourglass(3,5,9);


private static void printHourglass(int column, int times, int size) 
    for(int i = 0;i<column;++i) 
        // If it is the first iteration print the first line, otherwhise
        // Leave out the first only plus line
        printHourglassRow(times, size, i == 0 ? 0 : 1);
    


private static void printHourglassRow(int times, int size, int start) 
     // If it is not the first hourglass don´t print the first only plus row
    int printableStars = start == 0 ? size : size-2;
    int printableSpaces = start == 0 ? 0 : 1;
    // If the size is even we need to print one row less
    size = size % 2 == 0 ? size-1:size;
    for(int i = start;i<size;++i) 
        // Decides if we should print whitespaces or spaces first.
        // only The first and last row start with the plus 
        int mode = (i == size || i == 0) ? 1 : 0;
        //System.out.println(mode);
        //System.out.println(printableStars);
        // We are printing each column, we start with column 0
        int column = 0;
        // We print until we did reach the last column.
        while(column<times*size) 
            // If we are in print plus mode the next thing we print
            // will be a space, so switch mode and print stars as long as we should
            if(mode == 1) 
                mode = 0;
                for(int j = 0;j<printableStars;++j) 
                    printPlus();
                    ++column;
                
            // If we are in print whitespace mode the next thing we print
            // will be a space, so switch mode and print whitespaces as long as we should
             else 
                mode = 1;
                // If we reached the second hourglass (column > size/2)
                // Then we need to print twice as much whitespaces
                int sizeHalf = size % 2 == 0? size/2 : size/2+1; 
                for(int j = 0;column > sizeHalf ? j<printableSpaces*2:j<printableSpaces;++j) 
                    printSpace();
                    ++column;
                
            
        
        // We are not in the middle of the hourglass so
        // We print two stars less and one whitespace more.
        if(size - 2*i > 2) 
            ++printableSpaces;
            printableStars -= 2;
        // If we are reaching the point where we are in the middle
        // Of the houreglass we need to print one whitespace less 
        // and two plus more.
         else 
            --printableSpaces;
            printableStars += 2;
        
        // Linebreak
        System.out.println();
    


private static void printPlus() 
    System.out.print("+");


private static void printSpace() 
    System.out.print(" ");

【讨论】：

非常感谢！尽管我们使用您给我的所有代码还为时过早，但我可以根据需要对其进行调整。你帮了大忙！ :)