Use of foreach in Java

Foreach is a new, more concise syntax introduced by Java SE5, which brings great convenience in traversing arrays and containers, but has its limitations.

Statement format for foreach:

for (element type T element variable x: Traverse object obj) {

A Java statement that references X;

}

The traversal of a foreach simplified array

Example one (one-dimensional array):

1 ImportJava.util.Random;2  Public classForeach {3      Public Static voidMain (string[] args) {4Random Rand =NewRandom ();5         int[] t =New int[5];6         //initializing an array7          for(inti=0;i<t.length;i++)8T[i] = rand.nextint (100);9         Ten         //iterating through an array using foreach One          for(intx:t) ASystem.out.print (x + ""); -     } - } the /* - * Output Result: -  About -  * +  */ 

Example two (two-dimensional array)

1  Public classForeach {2      Public Static voidMain (string[] args) {3         //initializing an array4         int[] t = {5{2,3,4,5},6{1,6,7,8}7         };8         9         //iterating through an array using foreachTen          for(intx[]:t) { One              for(intm:x) ASystem.out.print (M + ""); - System.out.println (); -         } the     } - } - /* - * Output Result: + * 2 3 4 5 - * 1 6 7 8 +  *  A  */

However, it is worth noting that foreach is unable to complete the assignment, that is, the array is only "read-only" for the foreach statement.

Example three (foreach cannot complete assignment)

1 ImportJava.util.Random;2  Public classForeach {3      Public Static voidMain (string[] args) {4Random Rand =NewRandom ();5         int[] t =New int[5];6         //initializing an array7          for(inti=0;i<t.length;i++)8T[i] = rand.nextint (100);9         Ten         //iterating through an array using foreach One          for(intx:t) ASystem.out.print (x + ""); - System.out.println (); -          the         //Assignment with foreach (note that this is the wrong approach) -          for(intx:t) -x = Rand.nextint (100); -         //iterate through the array again +          for(intx:t) -System.out.print (x + ""); +     } A } at /* - * Output Result: - * All in all - * All in all -  *  -  */

As can be seen from the above example three, foreach cannot be assigned to an array, and foreach is performed as follows

1  for (T x:obj) {2     x = Obj[i]; 3     x = random number; 4     5 }

Therefore, it is not possible to assign a value to an array.

Use of foreach in Java