To declare a method or function in Scala, you can follow these steps:
1. Start by using the def keyword, which stands for "define".
2. Then, give your method or function a name.
3. After the name, enclose any input parameters in parentheses, using the format (param1: DataType, param2: DataType). If there are no input parameters, just use empty parentheses like () or use underscore _ to indicate no parameters.
4. Follow the input parameter list by a colon : and specify the data type of the result, using the format : DataType.
5. Finally, enclose the body of your method or function in curly braces {}, with the Scala code you want to execute provided inside.
Here are some examples:
// A function with no input parameters that returns a String value
def greet(): String = {
"Hello, Scala!"
}
// A method that takes an Integer parameter and returns a Boolean value
def isEven(num: Int): Boolean = {
num % 2 == 0
}
// A function that takes two Double parameters and returns their sum
def sum(a: Double, b: Double): Double = {
a + b
}
In the first example, the method greet takes no input parameters and returns a String value.
In the second example, the method isEven takes an Int input parameter named num and returns a Boolean value indicating whether that input parameter is even or not.
In the third example, the function sum takes two Double input parameters named a and b and returns their sum.