php流程控制

流程
（1） if statements
if(expression){
statement;
}

<?php
$i_a=5;$i_b=4;
if($i_a<$i_b){
echo "a is smaller than b"
}elseif($i_a==&i_b){
echo "a equals b"
}else{
echo "a is bigger than b"
}
?>
(2) 逻辑运算符 &&,||
<?php
$i_a =5;$i_b =4;
$i_c =6;$i_d=7;
if($i_a>$i_b&&$i_c>$i_d){
echo "a is bigger than b and";
echo "c is bigger than d"
}
if($i_a>$i_b||$i_c>$i_d){
echo "a is bigger than b or";
echo "c is bigger than d";
}
?>
(3) switch 语句
<?php
$a=2;
switch($a){
case 0:
echo "a equals 0";
break;
case 1:
echo "a equals 1";
break;
case 2:
echo "a equals 2";
default:
echo "a is not 0,1,or 2";
break;

}
?>
(4) while loops
while(expression){
statement;
}
<?php
$count=0;
while($count<=10){
echo $count.",";
$count++;
}
?>
(5) for loops
for(expr1,expr2,expr3){
statement;
}
for(initial;test;each){
statement;
}
(6) continue 跳过本次循环，相当于skip
<?php
for($i=1;$i<10;$i++){
if(i==5){
continue;
}
echo $i.",";
}
?>
(7) break 跳出循环
<?php
for(&i=1;$i<10;$i++){
echo $i;
if(i==10){
break;
echo ",";
}

}
?>