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1、 PHP片段四种表示形式。
标准tags:
short tags:需要在php.ini中设置short _open_tag=on,默认是on
ASP tags: 需要在php.ini中设置asp_tags=on,默认是off
script tags:
2、 PHP变量及数据类型
1)$vaRIAble ,变量以字母、_开始,不能有空格
2)赋值$variable=value;
3)弱类型,直接赋值,不需要显示声明数据类型
4)基本数据类型:Integer,Double,String,Boolean,Object(对象或类),Array(数组)
5)特殊数据类型:Resourse(对第三方资源(如数据库)的引用),Null(空,未初始化的变量)
3、 操作符
1)赋值操作符:=
2)算术操作符:+,-,*,/,%(取模)
3)连接操作符:. ,无论操作数是什么,都当成String,结果返回String
4)Combined Assignment Operators合计赋值操作符:+=,*=,/=,-=,%=,.=
5)Automatically Incrementing and Decrementing自动增减操作符:
(1)$variable+=1 <=>$variable++;$variable-=1 <=>$variable-,跟C语言一样,先做其他操作,后++或-
(2)++$variable,-$variable,先++或-,再做其他操作
6)比较操作符:= =(左边等于右边),!=(左边不等于右边),= = =(左边等于右边,且数据类型相同),>=,>,<,<=
7)逻辑操作符:|| ó or,&&óand,xor(当左右两边有且只有一个是true,返回true),!
4、 注释:
单行注释:// ,#
多行注释:/* */
5、 每个语句以;号结尾,与Java相同
6、 定义常量:define(“CONSTANS_NAME”,value)
7、 打印语句:print,与c语言相同
8、 流程控制语句
1)if语句:
(1)if(expression)
{
//code to excute if expression evaluates to true
}
(2)if(expression)
{
}
else
{
}
(3)if(expression1)
{
}
elseif(expression2)
{
}
else
{
}
2)swich语句
switch ( expression )
{
case result1:
// execute this if expression results in result1
break;
case result2:
// execute this if expression results in result2
break;
default:
// execute this if no break statement
// has been encountered hitherto
}
3)?操作符:
( expression )?returned_if_expression_is_true:returned_if_expression_is_false;
4)while语句:
(1) while ( expression )
{
// do something
}
(2)do
{
// code to be executed
} while ( expression );
5)for语句:
for ( initialization expression; test expression; modification expression ) {
// code to be executed
}
6)break;continue
9、 编写函数
1)定义函数:
function function_name($argument1,$argument2,……) //形参
{
//function code here;
}
2)函数调用
function_name($argument1,$argument2,……); //形参
3)动态函数调用(Dynamic Function Calls):
1:
2:
3:Listing 6.5
4:
5:
6:
7: function sayHello() { //定义函数sayHello
8: print “hello
“;
9: }
10: $function_holder = “sayHello”; //将函数名赋值给变量$function_holder
11: $function_holder(); //变量$function_holder成为函数sayHello的引用,调用$function_holder()相当于调用sayHello
12: ?>
13:
14:
4)变量作用域:
全局变量:
1:
2:
3:Listing 6.8
4:
5:
6:
7: $life=42;
8: function meaningOfLife() {
9: global $life;
/*在此处重新声明$life为全局变量,在函数内部访问全局变量必须这样,如果在函数内改变变量的值,将在所有代码片段改变*/
10: print “The meaning of life is $life
“;
11: }
12: meaningOfLife();
13: ?>
14:
15:
5)使用static
1:
2:
3:Listing 6.10
4:
5:
6:
#p#分页标题#e#
7: function numberedHeading( $txt ) {
8: static $num_of_calls = 0;
9: $num_of_calls++;
10: print “
$num_of_calls. $txt
“;
11: }
12: numberedHeading(“Widgets”); //第一次调用时,打印$num_of_calls值为1
13: print(“We build a fine range of widgets
“);
14: numberedHeading(“Doodads”); /*第一次调用时,打印$num_of_calls值为2,因为变量是static型的,static型是常驻内存的*/
15: print(“Finest in the world
“);
16: ?>
17:
18:
6) 传值(value)和传址(reference):
传值:function function_name($argument)
1:
2:
3:Listing 6.13
4:
5:
6:
7: function addFive( $num ) {
8: $num += 5;
9: }
10: $orignum = 10;
11: addFive( &$orignum );
12: print( $orignum );
13: ?>
14:
编程语言排行榜上
编程语言(programming language),是用来定义计算机程序的形式语言。它是一种被标准化的交流技巧,用来向计算机发出指令。一种计算机语言让程序员能够准确地定义计算机所需要使用的数据,并精确地定义在不同情况下所应当采取的行动。[1]
最早的编程语言是在电脑发明之后产生的,当时是用来控制提花织布机及自动演奏钢琴的动作。在电脑领域已发明了上千不同的编程语言,而且每年仍有新的编程语言诞生。很多编程语言需要用指令方式说明计算的程序,而有些编程语言则属于声明式编程,说明需要的结果,而不说明如何计算。
15:
结果:10
传址:funciton function_name(&$argument)
1:
2:
3:Listing 6.14
4:
5:
6:
7: function addFive( &$num ) {
8: $num += 5; /*传递过来的是变量$num的引用,因此改变形参$num的值就是真正改变变量$orignum物理内存中保存的值*/
9: }
10: $orignum = 10;
11: addFive( $orignum );
12: print( $orignum );
13: ?>
14:
15:
结果:15
7)创建匿名函数:create_function(‘string1’,’string2’); create_function是PHP内建函数,专门用于创建匿名函数,接受两个string型参数,第一个是参数列表,第二个是函数的主体
1:
2:
3:Listing 6.15
4:
5:
6:
7: $my_anon = create_function( '$a, $b', 'return $a+$b;' );
8: print $my_anon( 3, 9 );
9: // prints 12
10: ?>
11:
12:
8)判断函数是否存在:function_exists(function_name),参数为函数名
10、用PHP连接MySQL
1)连接:&conn=mysql_connect(“localhost”, “joeuser”, “somepass”);
2)关闭连接:mysql_close($conn);
3) 数据库与连接建立联系:mysql_select_db(database name, connection index);
4) 将SQL语句给MySQL执行:$result = mysql_query($sql, $conn); //增删改查都是这句
5) 检索数据:返回记录数:$number_of_rows = mysql_num_rows($result);
将记录放入数组:$newArray = mysql_fetch_array($result);
例子:
1:
2: // open the connection
3: $conn = mysql_connect(“localhost”, “joeuser”, “somepass”);
4: // pick the database to use
5: mysql_select_db(“testDB”,$conn);
6: // create the SQL statement
7: $sql = “SELECT * FROM testTable”;
8: // execute the SQL statement
9: $result = mysql_query($sql, $conn) or die(mysql_error());
10: //go through each row in the result set and display data
11: while ($newArray = mysql_fetch_array($result)) {
12: // give a name to the fields
13: $id = $newArray['id'];
14: $testField = $newArray['testField'];
15: //echo the results onscreen
16: echo “The ID is $id and the text is $testField
“;
17: }
18: ?>
11、接受表单元素:$_POST[表单元素名],
如ó$_POST[user] 接受url中queryString中值(GET方式):$_GET[queryString] 12、转向其他页面:header(“Location: http://www.webjx.com”);
13、字符串操作:
1)explode(“-”,str)óJava中的splite
2)str_replace($str1,$str2,$str3) =>$str1要查找的字符串,$str2用来替换的字符串,$str3从这个字符串开始查找替换
3)substr_replace:
14、session:
1)打开session:session_start(); //也可以在php.ini设置session_auto_start=1,不必再每个script都写这句,但是默认为0,则必须要写。
2)给session赋值:$_SESSION[session_variable_name]=$variable;
3)访问session:$variable =$_SESSION[session_variable_name];
4)销毁session:session_destroy();
15、显示分类的完整例子:
1:
#p#分页标题#e#
2: //connect to database
3: $conn = mysql_connect(“localhost”, “joeuser”, “somepass”)
4: or die(mysql_error());
5: mysql_select_db(“testDB”,$conn) or die(mysql_error());
6:
7: $display_block = “
My Categories
8:
Select a category to see its items.
“;
9:
10: //show categories first
11: $get_cats = “select id, cat_title, cat_desc from
12: store_categories order by cat_title”;
13: $get_cats_res = mysql_query($get_cats) or die(mysql_error());
14:
15: if (mysql_num_rows($get_cats_res) < 1) { //如果返回记录行数小于1,则说明没有分类
16: $display_block = “
Sorry, no categories to browse.
“;
17: } else {
18:
19: while ($cats = mysql_fetch_array($get_cats_res)) { //将记录放入变量$cats中
20:$cat_id = $cats[id];
21:$cat_title = strtoupper(stripslashes($cats[cat_title]));
22:$cat_desc = stripslashes($cats[cat_desc]);
23:
24: $display_block .= “
<a
25: href=\\\\”$_SERVER[PHP_SELF][U1] ?cat_id=$cat_id\\\\”>$cat_title//点击此url,刷新本页,第28行读取cat_id,显示相应分类的条目
26:
$cat_desc
“;
27:
28:if ($_GET[cat_id] == $cat_id) { //选择一个分类,看下面的条目
29: //get items
30: $get_items = “select id, item_title, item_price
31: from store_items where cat_id = $cat_id
32: order by item_title”;
33: $get_items_res = mysql_query($get_items) or die(mysql_error());
34:
35: if (mysql_num_rows($get_items_res) < 1) {
36: $display_block = “
Sorry, no items in
37: this category.
“;
38: } else {
39:
40: $display_block .= “
“;
41:
42: while ($items = mysql_fetch_array($get_items_res)) {
43: $item_id = $items[id];
44: $item_title = stripslashes($items[item_title]);
45: $item_price = $items[item_price];
46:
47: $display_block .= ”
48: href=\\\\”showitem.php?item_id=$item_id\\\\”>$item_title
49: (\\\\$$item_price)”;
[U2] 50: }
51:
52: $display_block .= “
“;
53: }
54: }
55: }
56: }
57: ?>
58:
59:
60:My Categories
61:
62:
63: <? print $display_block; ?>
64:
#p#分页标题#e#
65:
c语言编程入门
16、PHP连接Access:
以下为引用的内容: <? $dbc=new com(“adodb.connection”); $dbc->open(“driver=microsoft access driver (*.mdb);dbq=c:\\\\member.mdb”); $rs=$dbc->execute(“select * from tablename”); $i=0; while (!$rs->eof){ $i+=1 $fld0=$rs->fields[“UserName”]; $fld0=$rs->fields[“PassWord”]; …. echo “$fld0->value $fld1->value ….”; $rs->movenext(); } $rs->close(); ?> |
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