Three major process controls of PHP programs_PHP tutorial

Three major process controls for PHP programs

Three major process controls for PHP programs

① Sequential control (from top to bottom, from left to right)

②Branch Control

if(conditional expression){

//nMultiple statements

}else if (conditional expression){

//n Multiple statements

}else if(conditional expression){

//.

}//There may be more else if

else{

}

u switch branch statement

Basic grammatical structure

switch(expression){

case constant 1:

//nMultiple statements;

break;

case constant 2:

//nMultiple statements

break;

default:

//nMultiple statements;

break;

}

u Type of constant (int, float, string, boolean and null

default can be placed anywhere

Hello12 will be output on the right.

Conclusion: First match in case order, if none matches

When

is reached, default will be executed until break or }

is encountered.

Application scenario: When our branch is a few points (such as judging the direction of a tank), we should use switch. If your branch is a judgment of several areas (range), consider using if.

③Loop control process

for(initial value of loop; condition of loop; step size){

//nMultiple statements;

}

while(loop condition){

//Loop body, statement

}

do{

//Loop body

}while(loop condition);

42. According to normal thinking, we should ensure that when accepting data, $_REQUEST['parameter'] must be consistent with the html element name given on the data submission page. If they are inconsistent, a notice will appear. At the same time, the data we accept is null, which is equivalent to "".

//$_REQUEST This method can accept the user's post or get request data

43. break and continue

u Loop-related statements-break

Basic concept: It means to end the current for, while, do..while, switch, process. You can give a number to indicate which layer to exit to.

$i=0;

while( $i){

switch($i){

case 5:

echo quit at5
;

break;

case 10:

echo quit 10
;

break 2;

default:

break;

}

}

echo '$i='.$i;

The result is:

quit at 5
quit at 10
$i=10

From the above cases, we draw several conclusions:

1. The break statement will jump out to level 1 by default

2. The number after the break statement cannot exceed the actual number of loop levels that can be jumped out, otherwise, a fatalerror will be reported

Ø Loop related statements-continue

Basic concept: continue is used to end the remaining code of this loop and start a new loop from scratch (if the condition is true, continue execution), continue can also be followed by a number to indicate the number of loops to restart from

http://www.bkjia.com/PHPjc/1040916.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1040916.htmlTechArticleThe three major process controls of PHP programs The three major process controls of PHP programs ① Sequential control (from top to bottom, from Left to right) ②Branch control if (conditional expression) { //n multiple statements}else if (conditional expression...