Data Types
a method is a block of code that performs a specific task and can be called by other parts of the program
a method consists of a method signature, which includes the method name, return type, and parameter list, and a method body, which contains the code that is executed when the method is called
Method example
public int addNumbers(int num1, int num2) {
int sum = num1 + num2;
return sum;
}
System.out.println(addNumbers(10, 20));
control structures are constructs that allow you to control the flow of execution in a program
they let you execute specific statements or blocks of code based on certain conditions
some examples: if-else, for loop, while loop, switch case
The IntByReference class uses the integer primitive and its function is swapping the two inputted numbers, if the first is greater than the second
A wrapper class is used to change a primitive int into an Integer object
the Integer object is turned back into a primitive type "tmp" to switch values
public class IntByReference {
// sets primitive
private int value;
//wrapper class
public IntByReference(Integer value) {
this.value = value;
}
public String toString() {
return (String.format("%d", this.value));
}
// function to swap the values
public void swapToLowHighOrder(IntByReference i) {
// if first value larger than second, then swap
if (this.value > i.value) {
//sets the first value back to a primitive type
int tmp = this.value;
this.value = i.value;
i.value = tmp;
}
}
public static void swapper(int n0, int n1) {
IntByReference a = new IntByReference(n0); // creates objects with wrapper class using primitive int
IntByReference b = new IntByReference(n1);
System.out.println("Before: " + a + " " + b);
a.swapToLowHighOrder(b); //calls method
System.out.println("After: " + a + " " + b);
System.out.println();
}
public static void main(String[] ags) {
IntByReference.swapper(21, 16);
IntByReference.swapper(16, 21);
IntByReference.swapper(16, -1);
}
}
IntByReference.main(null);