mirror of
https://github.com/Brandon-Rozek/website.git
synced 2024-09-19 14:15:13 -04:00
30 lines
1,014 B
Markdown
30 lines
1,014 B
Markdown
# Lecture on October 4th
|
|
|
|
## Pass by Copy vs Pass by Reference
|
|
|
|
### Pass by Copy
|
|
|
|
When you pass a primitive type into a method (int, char, double, float, etc), it makes a copy of the value of the variable and brings it into the method
|
|
|
|
### Pass by Reference
|
|
|
|
When you pass an array into a method (int[], char[], double[], etc[]), it passes in the reference of the variable into the method. In other words, you give the actual array into the method and allows the method to change it.
|
|
|
|
### What's the Implication?
|
|
|
|
If you change the primitive in a method, it doesn't actually change the value of the variable.
|
|
|
|
If you pass in an array and change it in the method, it has been permanently changed outside the method as well.
|
|
|
|
### How do I make it so I can't change my array by accident?
|
|
|
|
Use the `final`keyword in the method header
|
|
|
|
```java
|
|
public static void printAll(final int[] array) {
|
|
for (int i = 0; i < array.length; i++) {
|
|
System.out.println("Number " + (i + 1) + " is " + array[i])
|
|
}
|
|
}
|
|
```
|
|
|