PHP Basics-PHP programming statement-PHP Tutorial

PHP Basics: describes PHP programming statements. The following describes the programming statements in the PHP programming language. 1. a simple statement contains at most one statement per line. for example, the following is the referenced content: $ argv ++; correct $ argc --; which is introduced below PHPProgramming statements in the programming language.

1. simple statement

Each line contains at most one statement, for example:

Reference content is as follows:

 
 

  
  
$ Argv ++; // correct
  
  
$ Argc --; // correct
  
  
$ Argv ++; $ argc --; // error
 
 

2 Compound statements

A compound statement is a sequence of statements contained in braces, such as "{statement }". For example, the following sections.

• The statements included in the statement should be indented to one level than the compound statement.
• The left braces "{" should be at the end of the row starting with the compound statement; the right braces "}" should start with another line and align with the first line of the compound statement.
• Braces can be used for all statements, including a single statement, as long as these statements are part of an if-else or for control structure. This makes it easy to add statements without worrying about introducing bugs due to missing brackets.

3. return statement

A return statement with a return value does not use parentheses "()" unless they make the return value more explicit in some way. For example:

Reference content is as follows:

 
 

  
  
return; 
  
  
return myDisk.size(); 
  
  
return ($size ? $size : $defaultSize); 
 
 

4 if And else statements

The if-else statement should have the following format:

 
 

  
  
If (condition) {/* condition for operations */
  
  
Statements;
  
  
}
  
  
If (condition) {/* condition for operations .*/
  
  
Statements;
  
  
} Else {/* conditions for operations */
  
  
Statements;
  
  
}
  
  
If (condition) {/* condition for operations */
  
  
Statements;
  
  
} Else if (condition) {/* conditions for operations */
  
  
Statements;
  
  
} Else {/* conditions for operations */
  
  
Statements;
  
  
}
 
 

Note: if statements are always included in "{" and "}" to avoid the following format that may cause errors:

 
 

  
  
If (condition) // to avoid this writing, he ignores "{}"
  
  
Statement;
 
 

The comment format can also be written in the following way:

Reference content is as follows:

 
 

  
  
If (condition ){
  
  
/* Operation conditions */
  
  
Statements;
  
  
} Else {
  
  
/* Operation conditions */
  
  
Statements;
  
  
}
 
 

As long as the relationship between branches can be clearly described, where to write comments can be

5. for statement

A for statement should have the following format:

Reference content is as follows:

 
 

  
  
for (initialization; condition; update) { 
  
  
statements; 
  
  
} 
 
 

An empty for statement (all work is being initialized, condition judgment, and updated in the clause) should be in the following format:

 
 

  
  
for (initialization; condition; update); 
 
 

When a comma is used in the initialization or update clause of a for statement, the complexity is increased because more than three variables are used. If necessary, separate statements can be used before a for loop (initialization clause) or at the end of a for loop (update clause.

6 while statement

A while statement should have the following format

Reference content is as follows:

 
 

  
  
while (condition) { 
  
  
statements; 
  
  
} 
 
 

An empty while statement should have the following format:

 
 

  
  
while (condition); 
 
 

7 do... while statement

A do-while statement should have the following format:

Reference content is as follows:

 
 

  
  
do { 
  
  
statements; 
  
  
} while (condition); 
 
 

8 switch statement

A switch statement should have the following format:

Reference content is as follows:

 
 

  
  
switch (condition) { 
  
  
case ABC: 
  
  
/* falls through */ 
  
  
statements; 
  
  
case DEF: 
  
  
　statements; 
  
  
　break; 
  
  
case XYZ: 
  
  
statements; 
  
  
break; 
  
  
default: 
  
  
statements; 
  
  
break; 
  
  
} 
 
 

When a case is executed down (because there is no break statement), comments should be added at the position of the break statement. The above sample code contains comments/* falls through */.

9 try... catch statement

A try-catch statement should have the following format:

Reference content is as follows:

 
 

  
  
try { 
  
  
statements; 
  
  
} catch (ExceptionClass e) { 
  
  
statements; 
  
  
} 
 
 

A try-catch statement may be followed by a finally statement. it will be executed no matter whether the try code block is successfully executed.

Reference content is as follows:

 
 

  
  
try { 
  
  
statements; 
  
  
} catch (ExceptionClass e) { 
  
  
statements; 
  
  
} finally { 
  
  
statements; 
  
  
} 
 
 

I hope this article will help you.

Programming statements in the PHP programming language. 1. a simple statement contains at most one statement per line. for example, the following is the referenced content: $ argv ++; // correct $ argc --; // positive...