PHP introductory basic tutorial: for loop to print hollow diamonds

This section introduces the for loop to print hollow diamonds and examples of for loop application for your reference.

In the previous section, we introduced the PHP for loop. In this section, we will look at some specific examples. Idea: 1. Write the code to print a solid pyramid 2. Modify the code and empty the pyramid 3. Modify the code and turn the pyramid upside down 4. Modify the inverted code and empty the pyramid 5. Modify the code and parameterize specific numbers

1. Print the pyramid with solid gold characters:

<?php
//$n=5;
//by bbs.it-home.org
for($i=1;$i<=5;$i++){
//打印空格
for($j=1;$j<=5-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-1;$k++){
   echo "*";
  }

  echo "<br/>";
 }
?>

2. Sell the pyramid short

<?php
 //$n=5;
 for($i=1;$i<=5;$i++){
  //打印空格
  for($j=1;$j<=5-$i;$j++){
   echo " ";
  }
 //打印*号
 for($k=1;$k<=2*$i-1;$k++){
  //打印第一行后最后一行都打*连接
  if($i==1 || $i==5){
   echo "*";
  }else{
  //怎么打空格和*号的问题
   if($k==1 || $k==2*$i-1){
    echo "*";
   }else{
    echo " ";
   }
  }
 }
 echo "<br/>";
 }
?>

3. Turn the pyramid upside down

<?php
 //$n=5;
 for($i=1;$i<=5;$i++){
  //打印空格
  for($j=1;$j<=5-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-1;$k++){
   //打印第一行后最后一行都打*连接
   if($i==1 || $i==5){
     echo "*";
   }else{
    //怎么打空格和*号的问题
    if($k==1 || $k==2*$i-1){
     echo "*";
    }else{
     echo " ";
    }
   }
  }
 echo "<br/>";
 }
 //倒转
 //by bbs.it-home.org
 for($i=5;$i>=0;$i--){
  //打印空格
  for($j=0;$j<=5-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-3;$k++){
   echo "*";
  }
 echo "<br/>";
 }
?>

4. Short the pyramid and remove the * sign in the middle. Modify the code here (if($i==1 || $i==5){ //Remove $i==5 and short the middle)

<?php
 //$n=5;
 for($i=1;$i<=5;$i++){
  //打印空格
  for($j=1;$j<=5-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-1;$k++){
  //打印第一行后最后一行都打*连接($i==1 || $i==5) 
   if($i==1){ //去掉$i==5 把中间抛空
    echo "*";
   }else{
    //怎么打空格和*号的问题
    if($k==1 || $k==2*$i-1){
     echo "*";
    }else{
     echo " ";
   }
  }
 }
 echo "<br/>";
 }
 //by bbs.it-home.org
 //倒转 抛空
 for($i=5;$i>=0;$i--){
  //打印空格
  for($j=0;$j<=5-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-3;$k++){
   //怎么打空格和*号的问题
   if($k==2*$i-3 || $k==1){
    echo "*";
   }else{
    echo " "; 
   }
  }
 echo "<br/>";
 }
?>

5. Parameterize the specific number: Change the specific number 5 to $n=5 instead, and then set the value of $n, which can be enlarged or reduced at will

<?php
 $n=5;
 for($i=1;$i<=$n;$i++){
  //打印空格
  for($j=1;$j<=$n-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-1;$k++){
  //打印第一行后最后一行都打*连接($i==1 || $i==5) 
   if($i==1){ //去掉$i==5 把中间抛空
    echo "*";
   }else{
    //怎么打空格和*号的问题
    if($k==1 || $k==2*$i-1){
     echo "*";
    }else{
     echo " ";
    }
  }
 }
 echo "<br/>";
 }
 //倒转 抛空
 for($i=$n;$i>=0;$i--){
  //打印空格
  for($j=0;$j<=$n-$i;$j++){
   echo " ";
  }
  //打印*号
  for($k=1;$k<=2*$i-3;$k++){
   //怎么打空格和*号的问题
   if($k==2*$i-3 || $k==1){
    echo "*";
   }else{
    echo " "; 
   }
  }
 echo "<br/>";
 }
?>

Thank you for paying attention to the PHP introductory tutorial. This series of PHP basic tutorials will help PHP newbies quickly master the PHP programming language. Programmer's Home will continue to launch PHP-related tutorials for everyone, and I wish you all the best in your learning and progress!