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one. Conditional statement
1.if statement syntax:
if (conditional statement 1) such as $a=$b or $a>$b
{
The command executed when conditional statement 1 is met, such as echo "a is greater than b";
}
elseif (conditional statement 2) For example $a<0 or $b<0
{
The command executed when conditional statement 2 is met, such as echo "because a or b is less than 0 and exceeds the optional range";
}
else does not need to be connected to a condition. The meaning of the branch is when neither conditional statement 1 nor conditional statement 2 is satisfied
{
Executed when neither conditional statement 1 nor conditional statement 2 is satisfied, such as echo "The content you entered is empty, please re-enter";
}
header("Content-Type:text/html; charset=utf-8"); $a=100; $b=10; if ($a>$b) { echo "a>b"; } elseif ($a<$b) { echo "a Output result a>b
Example 2
header("Content-Type:text/html; charset=utf-8"); $secore=92; if($secore>=60 && $secore<70) { echo "Your score is passing"; } elseif($secore>=70 && $secore<80) { echo "Your grades are good"; } elseif($secore>=80 && $secore<90) { echo "Your grades are good"; } elseif( $secore>=90 && $secore<=100) { echo "Your score is excellent"; elseif($secore>100 || $secore<0) echo " echo echo echo " "Your grades are failing, please keep working hard"; } ?> Output results: Your grades are excellent
(2)switch statement syntax
switch (condition variable) for example: $a
{
The condition of the case condition variable. For example, $a>0: executed when the condition is met, such as echo a>0;break;
The condition of the case condition variable. For example, $a<0: executed when the condition is met, such as echo a<0;break;
default: output when none of the above conditions are met, such as echo "a and b are illegal";
}
header("Content-Type:text/html; charset=utf-8"); $secore=92; switch($secore) { case $secore>=60 && $secore<70: $pj="You Your grades are passing";break; case $secore>=70 && $secore<80: $pj="Your grades are good";break; case $secore>=80 && $secore<90: $pj="Yours Excellent grades";break; case $secore>=90 && $secore<=100: $pj="Your grades are excellent";break; case $secore<0 || $secore>100: $pj="Yours The score is illegal";break; default: $pj="Your score is failing, keep working hard"; } echo $pj; ?> Output result: Your score is excellent
(3)Ternary operator syntax
echo (condition, for example: $a>$b)? If the condition is true statement "a>b": If the condition is not true "a
header("Content-Type:text/html; charset=utf-8"); $a=10;$b=20; echo ($a>$b)?"a>b" :"a< b"; ?> 2. Flow control statement
Loop statement
1.for statement syntax
for ($variable name=0;$array name
{
echo $array name[$variable name];
}
header("Content-Type:text/html; charset=utf-8"); $a=array('Zhang Chao','Qiao Bin','Chen Wei','Zhao Yongfeng'); for ( $i=0;$i
2.while statement syntax
$Variable name=0
while($variable name
{
echo $array name[$variable name];
$Variable name++
}
header("Content-Type:text/html; charset=utf-8"); $a=array('Zhang Chao','Qiao Bin','Chen Wei','Zhao Yongfeng'); $i =0; while ($i
3.foreach loop syntax
foreach($variable name as $variable rename)
{
echo $variable rename;
}
header("Content-Type:text/html; charset=utf-8"); $a=array('Zhang Chao','Qiao Bin','Chen Wei','Zhao Yongfeng'); foreach ( $a as $v) { echo $v." "; } ?> Output results Zhang Chao, Qiao Bin, Chen Wei, Zhao Yongfeng
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