Basic syntax for PHP (iii)

VIII. Conditional Statement 1, if statement

If the specified condition is true, the code is executed

2. If...else statement

If the condition is true, the code is executed, and if the condition is false, the other end code is executed

3. If...elseif....else statement

Select one of several segment code blocks to execute

$num=3;if($num>3)echo"\$num>1";elseif($num==3)echo"\$num=3";elseecho"\$num<3";

Operation Result:$num=3

4. Switch statement

Selectively execute one of several blocks of code

Working principle:

• Perform a single calculation on an expression (usually a variable)
• Compare the value of an expression with the value of a case in the structure
• If there is a match, the code associated with the case is executed
• After the code executes, the break statement prevents the code from jumping into the next case to continue execution
• If no case is true, use the default statement

$x=4;switch ($x){case1:  echo"Number 1";  break;case2:  echo"Number 2";  break;default:  echo"No number between 1 and 2";}

Operation Result:No number between 1 and 2

IX. Circular Statement 1, while

Loop code block whenever you specify a condition that is true

2, Do...while

Executes the code block one time and then repeats the loop whenever the condition is specified as True

3. For

Loop code block specified number of times

4. foreach

Iterate through each element in the array and loop through the code block

<?PHP$its = array("Apple","Google","Microsoft","Solidot"); foreach ($its as $it) {  echo "$it <br>";}?>

Operation Result:
Apple
Google
Microsoft
Solidot

X. Function 1, type of function

a function is a block of statements that can be reused in a program.
The function does not execute immediately when the page loads.
Functions are executed only when they are called.

• Built-in functions: more than 1000 built-in functions
• Custom functions: Start with a "function" keyword, which can start with a letter or underscore (not a number), is insensitive to case, and should reflect the task performed by the function.

2. Several elements of the function

• php function Parameters : Parameters are defined after the function name, inside the parentheses. You can add as many arguments as you want by separating them with commas.
• PHP function default parameter : assigns a value directly after the parameter, and automatically assigns the default value when we call a function that does not contain parameters.
• PHP function return value : Returns the value using the return statement.

<?phpfunction passwd($account,$password=123456){return$password;}$pLee = passwd("Lee");echo  "$pLee";?>

Operation Result:123456

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Basic syntax for PHP (iii)