Three major process controls for PHP programs

Three major process controls for PHP programs

① sequential control (top to bottom). From left to right)

② Branch Control

if (conditional expression) {

N Multiple statements

}else if (conditional expression) {

N Multiple statements

}else if (conditional expression) {

//.

}//There may be a lot of other else if

else{

}

U Switch Branch statement

The basic grammatical structure

switch ( expression ) {

Case Constants 1:

//n Multi-statement ;

Break

Case Constants 2:

//n Multi-statement

Break

Default

//n Multi-statement ;

Break

}

u types of constants (int, float, string , boolean, and null

default you can put it anywhere.

The right side will output hello12 .

conclusion: First, according to Case order to match, assuming none of the matches

to, then run default , until you encounter Break or }

Application scenario: When our branch is a few points (for example, to infer the direction of a tank), you should use Swtich, assuming that your branch is inferred from several regions (ranges). Then consider using IF.

③ Cycle Control Flow

For ( Cyclic initial value ; conditions of the cycle ; Step Size ){

//n Multi-statement ;

}

While ( loop condition ) {

// Loop Body , Statement

}

do{

       // Loop Body

}while ( cyclic conditions );

42, We follow the normal thinking should be guaranteed to accept the data when the $_request[' " " to and submit the data page The HTML element name to be consistent. If the assumptions are inconsistent, a notice prompt appears.

The data we accept at the same time is null, equivalent to "".

//$_request This method can accept the user's post or GET request data

43. Break and Continue

U Loop-related statement-break

Main concept: Indicates the end of the current for, while, do. While,switch, process , can give a number, indicating exit to the first layer .

$i = 0;

while (+ + $i) {

Switch ($i) {

Case 5:

echo "Quit At5<br/>";

Break

Case 10:

echo "Quitat 10<br/>";

Break 2;

Default

Break

}

}

echo ' $i = '. $i;

The result is:

Quit at 5
Quit at 10
$i =10

From the above case, we get a few conclusions:

1. Break statement jumps out of layer 1 by default

2. The number after the break statement. Cannot exceed the number of loop layers that can actually jump out. Otherwise. Will report FatalError

? Circular related Statements-continue

Basic concept: The Continue is used to end the remainder of this cycle of code. Start a new cycle (assuming the condition is true and continue running),continue can also be followed by numbers, indicating that the first cycle starts again

Three major process controls for PHP programs