How to create a sequential list in Java

2 years ago
Benjamin Taylor
3 minutes

In Java, we can use an array to create a list. Here are the steps to create a list:

  1. An ordered collection in Java that can dynamically grow in size is termed as an ArrayList.
  2. information
public class ArrayList {
    private int[] data;
}
  1. dimension
  2. fresh
  3. information
public ArrayList(int size) {
    data = new int[size];
}
  1. Add some basic operations to the sequential table, such as adding elements, deleting elements, and retrieving elements.
  1. The method for adding elements can be named as ‘add’, it takes an integer parameter ‘element’ and adds it to the end of the array. Firstly, the method checks if the array is full, and if it is, it throws an exception. Otherwise, it adds the element to the last position of the array and increments the size of the array by 1.
public void add(int element) {
    if (isFull()) {
        throw new RuntimeException("ArrayList is full");
    }
    data[size] = element;
    size++;
}
  1. The remove method can be named as remove, which takes an integer parameter index to indicate the index of the element to be deleted in the sequential list. In the method, first check whether the index is valid, meaning it is within the legal range; if not, an exception is thrown; otherwise, delete the element at the specified index, move the following elements forward by one position, and finally decrease the size of the sequential list by 1.
public void remove(int index) {
    if (!isValidIndex(index)) {
        throw new RuntimeException("Invalid index");
    }
    for (int i = index; i < size - 1; i++) {
        data[i] = data[i + 1];
    }
    size--;
}
  1. The method for accessing elements can be named “get”, taking an integer parameter index which represents the index of the element to be accessed in the list. In the method, first check if the index is valid, meaning it is within the legal range; if not, throw an exception; otherwise, return the element at the specified index position.
public int get(int index) {
    if (!isValidIndex(index)) {
        throw new RuntimeException("Invalid index");
    }
    return data[index];
}
  1. Improve other methods in the sequence table class, such as checking if the sequence table is full, verifying the validity of the index, and so on.
  1. The method that determines whether an array is full can be named isFull. It returns true if the size of the array is equal to the length of the array, indicating it is full; otherwise, it returns false.
public boolean isFull() {
    return size == data.length;
}
  1. One way to determine if an index is valid can be named as isValidIndex. If the index is greater than or equal to 0 and less than the size of the list, it is considered valid and should return true; otherwise, it should return false.
public boolean isValidIndex(int index) {
    return index >= 0 && index < size;
}

By following the above steps, a simple sequence list class ArrayList can be created. It should be noted that the code above is just one way to implement a sequence list, as there are other ways to implement it such as using dynamic arrays or linked lists.

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