Monday 20 January 2014

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A complete PHP Tutorial For Beginners To Learn PHP Basic Part 2

Posted by Unknown at 01:12

                                

PHP If...Else Statements

Conditional Statements

  • if statement - use this statement to execute some code only if a specified condition is true.
  • if...else statement - use this statement to execute some code if a condition is true and another code if the condition is false
  • if...elseif....else statement - use this statement to select one of several blocks of code to be executed.
  • switch statement - use this statement to select one of many blocks of code to be executed

The if Statement

Syntax

  • if (condition) code to be executed if condition is true;
  • The following example will output "Have a nice weekend!" if the current day is Friday:

Example

  1. <html> 
  2. <body> 
  3. <?php 
  4. $d=date("D"); 
  5. if ($d=="Fri") echo "Have a nice weekend!"; 
  6. ?> 
  7. </body> 
  8. </html>

The if...else Statement

Syntax

  • if (condition) 
    • code to be executed if condition is true; 
  • else 
    • code to be executed if condition is false;

Example

  • The following example will output "Have a nice weekend!" if the current day is Friday, otherwise it will output "Have a nice day!":
  1. <html> 
  2. <body> 
  3. <?php 
  4. $d=date("D"); 
  5. if ($d=="Fri") 
  6. echo "Have a nice weekend!"; 
  7. else 
  8. echo "Have a nice day!"; 
  9. ?> 
  10. </body> 
  11. </html>
  • If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces:
  1. <html> 
  2. <body> 
  3. <?php 
  4. $d=date("D"); 
  5. if ($d=="Fri") 
  6. { 
  7. echo "Hello!<br />"; 
  8. echo "Have a nice weekend!"; 
  9. echo "See you on Monday!"; 
  10. } 
  11. ?> 
  12. </body> 
  13. </html>

The if...elseif....else Statement

Syntax

  • if (condition) 
    • code to be executed if condition is true; 
  • elseif (condition) 
    • code to be executed if condition is true; 
  • else 
    • code to be executed if condition is false;

Example

  • The following example will output "Have a nice weekend!" if the current day is Friday, and "Have a nice Sunday!" if the current day is Sunday. Otherwise it will output "Have a nice day!":
  1. <html> 
  2. <body> 
  3. <?php 
  4. $d=date("D"); 
  5. if ($d=="Fri") 
  6. echo "Have a nice weekend!"; 
  7. elseif ($d=="Sun") 
  8. echo "Have a nice Sunday!"; 
  9. else echo "Have a nice day!"; 
  10. ?> 
  11. </body> 
  12. </html>

The if...elseif....else Statement

Syntax

  1. switch (n) 
  2. { 
  3. case label1: 
  4. code to be executed if n=label1; 
  5. break; 
  6. case label2: code to be executed if n=label2; 
  7. break; 
  8. default: 
  9. code to be executed if n is different from both label1 and label2; 
  10. }
  • This is how it works: First we have a single expression n (most often a variable), that is evaluated once. The value of the expression is then compared with the values for each case in the structure. If there is a match, the block of code associated with that case is executed. Use break to prevent the code from running into the next case automatically. The default statement is used if no match is found.

Example


  1. <html> 
  2. <body> 
  3. <?php switch ($x) 
  4. { 
  5. case 1: 
  6. echo "Number 1"; 
  7. break;
  8. case 2: 
  9. echo "Number 2"; 
  10. break; 
  11. case 3: 
  12. echo "Number 3"; 
  13. break; 
  14. default: 
  15. echo "No number between 1 and 3"; 
  16. } 
  17. ?> 
  18. </body> 
  19. </html>

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