[Java Basics] foreach loop and javaforeach Loop

[Java Basics] foreach loop and javaforeach Loop

Starting with a small program:

1 class lesson6foreach 2 {3 public static void main (String [] args) 4 {5 int array [] = {2, 3, 1, 5, 4, 6 }; 6 7 for (int I = 0; I <array. length; I ++) // cyclically outputs the array element 8 {9 System. out. println (array [I]); 10} 11} 12}View Code

However, we do not care about the I value in the for loop. Therefore, after Java 5, foreach is used to enhance the for loop.
Format:

For (element type variable: array name or Iterable instance) // The Iterable instance teacher says no worries, okay, no matter first.

{

}

The preceding Code is as follows:

1 class lesson6foreach 2 {3 public static void main (String [] args) 4 {5 int array [] = {2, 3, 1, 5, 4, 6}; 6 7 for (int x: array) // cyclically output array element 8 {9 System. out. println (x); 10} 11} 12}View Code

What if I encounter a two-dimensional array? Here is an example of a two-dimensional array:

1 class lesson6foreach 2 {3 public static void main (String [] args) 4 {5 char [] [] charArray = 6 {7 {'put', 'meng ', 'hao', 'ran', 'zhi', 'guang ', 'ling'}, 8 {'st', 'people', 'west', 'loan ', 'huang', 'h', 'loud'}, 9 {'yay', 'hua', '3', 'month', 'under', 'yang ', 'status'}, 10 {'orphan ', 'fan', 'yuan', 'shad', 'bi', 'kong', 'do '}, 11 {'wei', '', 'Chang', 'jiang', 'day', 'inter', 'stream'} 12 }; 13 14 for (char [] x: charArray) // two-dimensional 15 {16 for (char y: x) 17 System. out. print (y); 18 System. out. println (); 19} 20} 21}View Code

The result is as follows:

Java foreach Loop

<%
String [] ss = {"", "yes ",""};
%>
<C: forEach items = "$ {requestScope. alllog}" var = "dis">
<Tr>
<Td height = "41" valign = "top">
<Input type = "checkbox" name = "checkbox" value = "$ {dis. loginId}"/> </td>
<Td valign = "top"> <c: out value = "$ {dis. loginId}"> </c: out> </td>
<Td valign = "top"> <c: out value = "$ {dis. userId}"> </c: out> </td>
<Td valign = "top"> <c: out value = "$ {dis. loginTime}"> </c: out> </td>
<Td valign = "top"> <c: out value = "$ {dis. loginUserIp}"> </c: out> </td>
<Td valign = "top"> <c: out value = "<% = ss [$ {dis. ifSuccess}] %> "> </c: out> </td>
<Td valign = "top"> <c: out value = "$ {dis. loginDesc}"> </c: out> </td>
</Tr>
</C: forEach>

Comparison and testing of foreach loop and for loop in java

In... foreach, the I in your int I: c is not the subscript of the array, but the code encoding of your char conversion.
You should replace it with char I: c. In this way, I outputs characters.

Public static void main (String [] args ){
String str = "hello world !!! ";
Char c [] = str. toCharArray ();
Int count = 0;
For (char I: c ){
Count ++;
System. out. println ("c [" + count + "] =" + I + "\ t ");

}
}