How to use Enhanced for Loop?

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Using the following link to learn what the Enhanced for Loop is(The For-Each Loop). The following code is an interesting example of using Enhanced for Loop. The enhanced for loop will go through the array arr and set i to each member of the "int" array.

class Program {
  public static void main(String[] args) {
    int []arr = {1,2,3,4};
    for ( int i : arr ) {
      arr[i] = 0;
    }
    for ( int i : arr ){
      System.out.println(i);
    }
  }
}

Why it output : 0030? Let's take a look:

int []arr = {1,2,3,4};
    for ( int i : arr ) {
      arr[i] = 0;
    }

• Step 1. On the first iteration, i will be 1 because arr[0]=1, and set arr[1] to 0.
• Step 2. On the second iteration, i will be 0 because arr[1]=0 set by Step 1., and set arr[0] to 0.
• Step 3. On the third iteration, i will be 3 because arr[2]=3, and set arr[3] to 0.
• Step 4. On the last iteration, i will be 0 because arr[3]=0 set by Step 3, and set arr[0] to 0.

Here is another sample code using "Enhanced For Loop" for multi-dimensional arrays:

class Program {
  ...
  static void useEnhancedFor(int x[][]) {
    for(int[] l:x) {
      for(int m:l) {
        System.out.print(m+" ");
      }
    }
    System.out.println();
  }
}