java - How does this delete an element from an array? -

i using book data structures , algorithms in java learn (you guessed it) - data structures , algorithms. piece of code confuses me. have tested , works don't see in code specify delete 55 exactly?

i see search in array , move data elements index don't see tell compiler delete 55.

    searchkey = 55; // delete item key 55     for(j=0; j<nelems; j++) //       if(arr[j] == searchkey)         break;     for(int k=j; k<nelems-1; k++) // move higher ones down       arr[k] = arr[k+1];     nelems--; // decrement size 

to precise, code not delete array element; overrides it.

note how j declared outside first loop, , used in second loop initialize value of k. first loop walks j through array, until j "points" element value of 55. when happens, code exits loop through break, when second loop reads j, still points location in array 55 stored. second loop copies elements k+1-st location k-th, "overriding" value of 55 on first iteration, , moving rest of values in consecutive iterations.

consider example:

index:  0  1  2  3  4  5 value: 30 40 55 60 70 80 

after first loop j set 2. each iteration of second loop changes array follows:

index:        0  1  2  3  4  5 iteration 0: 30 40 55 60 70 80 iteration 1: 30 40 60 60 70 80 iteration 2: 30 40 60 70 70 80 iteration 3: 30 40 60 70 80 80 

at point nelems decremented, making sure last element (i.e. 80) disregarded if program runs again.