PHP Introductory tutorial operator and control structure flow

This article describes the PHP introductory tutorial operator and control structure flow. Share to everyone for your reference, as follows:

demo1.php

<?php  $username = "Chaoyv";  echo "His name is $username!";  $username 2 = "WU";  echo "His name is $username 2!";  echo "<br/>";  echo "His name is". $username 2. ", read who asked June chanting, \ \ \ \ \ \ \ \ \ \ \" ";  echo "<br/>";  echo "His name is". $username 2. ", read who asked June chanting, \ t water fell fragrance floating. ";  Echo ' His name is $username 2! ';//Cannot parse $username 2?>

demo2.php

<?php  $a = 5;  $b = 6;//$c = $a + $b,//Echo $c,//$a + = $b;//$a = $a + $b;//echo $a;//$a =++ $b;//$b = $b +1//echo $a;  7//echo $b;  7  $a = $b + +;  echo $a;  6  echo $b;//7?>

demo3.php

<?php//$a = 5;//$b = ' 5 ';////on the Web page (True True) is the embodiment of 1, the false embodiment is empty///identity must be the same data type///$a = = = $b Return is a fake, false//Echo! ($a = = = $b);  What will this print out?  $a = 5;  $b = 5;  $c = ($a = = $b);  echo $c;  $d = 8;  $e = 7;  $f = ($d = = $e);  echo $c && $f;  echo $c | | $f;? >

demo4.php

<?php  $total =;  Ternary operator  //If the judgment is true, then the whole returns the first string, otherwise the second string  $sum = $total >50? ' Success ': ' Failure ';  Echo $sum;? >

demo5.php

<?php  //In the development process, it is best to expose errors.  //$a = 100/0; Warning:division by zero in C:\AppServ\www\Basic3\Demo5.php on line 2  $a = @ (100/0);  echo $a;? >

demo6.php

<?php  //if conditional judgment statement  $userAge =;  The parentheses after the if is a Boolean expression that returns a result of 1 or an empty  //{} block statement//if ($userAge >18) {//   echo ' success ';/}  //If ... otherwise//if ($userAge >18) {//   echo ' success ';//}else{//   echo ' failure ';/}  //Multi  -line if ($userAge <18) {    Echo ' <18 ';  } ElseIf ($userAge <30) {    echo ' <25 ';  } else{    echo ' through ';  }? >

demo7.php

<?php  //Multi  -line//break exit problem, called Midway exit this condition judgment  $weekday = 3;  Switch ($weekday) {case    1:      echo ' Today Monday ';      break;    Case 2:      echo ' Today Tuesday ';      break;    Case 3:      echo ' Today Wednesday ';      break;    Case 4:      echo ' Today Thursday ';      break;    Default:      echo ' not clear ';  }? >

demo8.php

<?php  //while Loop  //When the expression is false, exit the loop  $a = ten;  while ($a > 0) {    echo $a;    $a--;    Echo ' <br/> ';  }? >

demo9.php

<?php  //for for  ($a =10; $a >0; $a-) {    echo $a;    Echo ' <br/> ';  }? >

demo10.php

<?php  //do  while $a = ten;  do{    echo $a;    Echo ' <br/> ';    $a--;  } while ($a >0);? >

demo11.php

<?php//for ($i = 0; $i <10; $i + +) {////   in this loop nest an if judgment statement//   if ($i ==5) {//     break;//exit loop//   }//   echo $i. ' <br/> ';//}//for ($i = 0; $i <10; $i + +) {////   within this loop nested an IF Judgment statement//   if ($i ==5) {//     exit ///exit the entire program//   }//   echo $i. ' <br/> ';//}//echo ' I'll do it ';  for ($i = 0; $i <10; $i + +) {    //within this loop, nest an if judgment statement    if ($i ==5) {      continue;//exits the current loop and continues the next loop OK    }    echo $i. ' <br/> ';  }? >

I hope this article is helpful to you in PHP programming.