Question

I’m currently working on a project for a class to create a TextLine class that represents the a line of text that must be represented as an array of characters.

For one of the methods, I am supposed to take in a string as an argument of a parameter and then append that string to my already created char array.

I was trying to search online for how I could do this, or even an example of the String or StringBuffer class that showed the implementation, but due to my novice skills at Google, I couldn’t really find anything useful.

What I ‘m thinking is that I first have to convert the string to the array, and then somehow using one of the array methods to add each char individually to the char array.

This is what I have:

public void append(String fragment){

    char[] temp = fragment.toCharArray();

}

I’m not quite sure what array method could be used, if there even is one. Could someone please help me?

Answer 1

Normally you would use a StringBuilder as the internal storage for your class but i assume that you need the basic details of how to do this.

The basic process is like this:

• allocate a new array with the size of old array + size of the new data
• copy the old data into the new array
• copy the new data at the end of the new array
• set this as the actual data

Here is the code (this assumes that the data member is declared like this: char[] data = new char[0]:

    public void append(String fragment) {
       char[] fragmentChars = fragment.toCharArray();
       char[] newData = new char[data.length + fragmentChars.length];

       System.arraycopy(data, 0, newData, 0, data.length);
       System.arraycopy(fragmentChars, 0, newData, data.length, fragmentChars.length);

       data = newData;
   }