How do you initialise a two-dimensional array with default values?

You initialise a two-dimensional array with default values by declaring the array and assigning the default values in the declaration.

In many programming languages, a two-dimensional array is essentially an array of arrays. When you initialise a two-dimensional array, you're creating a table with a certain number of rows and columns. The default values are the values that each element in the array will hold initially, before any other values are assigned to them.

For example, in Java, you can initialise a two-dimensional array with default values like this:

```java
int[][] array = new int[5][5];
```

This creates a 5 by 5 array, and because it's an array of integers, the default value for each element is 0. If you wanted to initialise the array with a different default value, you would need to use a loop to assign a value to each element, like this:

```java
int[][] array = new int[5][5];
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array[i].length; j++) {
array[i][j] = 1; // or whatever default value you want
}
}
```

In Python, you can use a similar approach, but the syntax is a bit different. Here's how you can initialise a two-dimensional array with default values in Python:

```python
array = [[0 for j in range(5)] for i in range(5)]
```

This creates a 5 by 5 array with a default value of 0 for each element. The `for` loops inside the square brackets are list comprehensions, a feature of Python that allows you to generate lists (or in this case, lists of lists) in a single line of code.

Remember, the way you initialise a two-dimensional array can vary depending on the programming language you're using. But in general, the process involves declaring the array and assigning default values to each element.