Adding parameters

Intermediate Java

Jim White

Java Developer

Parameters

Allow passing input values to methods
Add flexibility
Allow methods to respond to input
Makes methods more reusable and useful

sayHello(String name)

static void sayHelloV1(){
  System.out.println("Hello, there!");
}

static void sayHello(String name){ // Add String parameter called name
  System.out.println("Hello, " + name + "!"); // Use name in code
}

Now, we can call sayHello() with different names:

sayHello("Alice"); // Prints "Hello, Alice!"
sayHello("Sam"); // Prints "Hello, Sam!"

getSquare(int number)

static int getSquare(int number) {
  return number * number
}

getSquare(10); // Returns 100
getSquare(2); // Returns 4

Calling methods with parameters

class HelloWorld {
    public static void main (String[] args) {
        sayHello("Alice");
        int threeSquared = getSquared(3); // threeSquared = 9
    }
        static void sayHello(String name){ 
            System.out.println("Hello, " + name + "!"); 
        }
        static int getSquare(int number) {
            return number * number
        }
}

Hello, Alice!

More parameters - of any type

// Different types
static void printUser(String name, int age){ 
  System.out.println("User is " + name);
  System.out.println("They are " + age);
}

printUser("Ann", "32");

User is Ann
They are 32

// Same type, but more of them
static int addNumbers(int a, int b, int c){ 
  return a + b + c
}

int sum = addNumbers(2, 4, 6); 
System.out.println(sum);

Recap

Parameters allow us flexibility
Parameters go in the parenthesis after method name
We can have as many parameters as we want, also of different types

// Define method with parameters
static void printUser(String name, int age, String address){ 
  System.out.println("User is " + name);
  System.out.println("They are " + age);
  System.out.println("They live in " + address);
}

// Call the method
printUser("Sue", 43, "Canada");

Let's practice!

Intermediate Java