The basic way to return values from a method is to use a return
statement! (A well-constructed programming language shouldn’t have a lot of surprises.)
Let’s start with an example in the below code. It contains a definition of the Yell()
method, which returns a string, and it calls that method in Main()
.
When we execute this program, the code in Main()
runs first:
Yell()
is called.- In
Yell()
, the uppercase version of"who's there?"
is created and returned. - Back in
Main()
, that returned value is stored in the variableoutput
and then printed to the console:
static string Yell(string phrase) { return phrase.ToUpper(); } public static void Main() { string output = Yell("who's there?"); Console.WriteLine(output); // Prints WHO'S THERE? }
Here’s a more generic definition: the keyword return
tells the computer to exit the method and return a value to wherever the method was called.
When a method is declared, it must announce the type of value it will return. In this case, Yell()
returns a string, so it has the string
modifier (right before the name Yell
).
That first line of the method is called a method declaration, so we can say that the method declaration must contain the type of the return value.
Generally, the method declaration is a combination of details including: the access modifiers, return type, method name, and parameter types. This lesson will not cover access modifiers, like static
, so that we can focus on the return type, like string
.
Instructions
Let’s define a static
method DecoratePlanet()
that takes a planet name as input and returns a fancy welcome to the planet.
First, write the method declaration. It should have a string
parameter and return a string
.
Write the method body so that it returns a fancy welcome to the planet. For example, calling
DecoratePlanet("Mars");
returns:
"*.*.* Welcome to Mars *.*.*"
Call the method with the argument "Jupiter"
and print its output to the console.