## Which keyword below that you need use to define a package? ```go package main func main() { } ``` 1. func 2. package *CORRECT* 3. fmt.Println 4. import > **1:** func keyword is used to declare a new function. > > > **2:** That's right! package keyword allows you to define a package for a Go file. > > > **3:** It's not a keyword, it's a function of the fmt package. > > > **4:** import keyword is used to import a package. > > ## What is the purpose of using package main in the following program? ```go package main func main() { } ``` * To create a library package * To properly exit from the program * To create an executable Go program *CORRECT* ## What is the purpose of func main in the following program? ```go package main func main() { } ``` 1. It defines a package called main 2. It allows Go to start executing the program *CORRECT* 3. It prints a message to the console > **1:** main function doesn't create a package. > > > **2:** That's right. Go automatically calls the main function to execute a program. > > > **3:** It doesn't print anything (at least directly). > > ## What is the purpose of import "fmt" in the following program? ```go package main import "fmt" func main() { fmt.Println("Hi!") } ``` 1. It prints "fmt" to the console 2. It defines a new package called "fmt" 3. It imports the `fmt` package; so you can use its functionalities *CORRECT* > **1:** `fmt.Println` prints a message not the `import "fmt"`. > > > **2:** `package` keyword does that, not the `import` keyword. > > > **3:** Yes. For example, after you import the fmt package you can call its Println function to print a message to the console. > > ## Which keyword is used to declare a new function? * func *CORRECT* * package * Println * import ## What is a function? 1. It's like a mini-program. It's a reusable and executable block of code. *CORRECT* 2. It allows Go to execute a program. 3. It allows Go to import a package called function. 4. It prints a message to the console. > **2:** Go looks for package main and func main to do that. A function doesn't do that on its own. > > > **3:** `import` keyword does that. > > > **4:** For example: `fmt.Println` does that. > > ## Do you have to call the main function yourself? 1. Yes, so that, I can execute my program. 2. No, Go calls the main function automatically. *CORRECT* > **1:** No, you don't need to call the main function. Go automatically executes it. > > ## Do you have to call a function to execute it? _(except the main func)_ 1. Yes, so that, Go can execute that function. *CORRECT* 2. Yes, so that, Go can execute my program. 3. No, Go calls the functions automatically. > **1:** That's right. You need to call a function yourself. Go won't execute it automatically. Go only calls the main function automatically (and some other functions which you didn't learn about yet). > > > **2:** That's only the job of the `func main`. There's only one `func main`. > > > **3:** Go doesn't call any function automatically except the main func (and some other functions which you didn't learn about yet). So, except the main func, you need to call the functions yourself. > ## What does the following program print? ```go package main func main() { } ``` 1. It prints a message to the console 2. It's a correct program but it doesn't print anything *CORRECT* 3. It's an incorrect program > **1:** It doesn't print a message. To do that you can use fmt.Println function. > > > **2:** Yes, it's a correct program, however since it doesn't contain fmt.Println it doesn't print anything. > > > **3:** It's a correct program. It uses the package keyword and it has a main function. So, this is a valid and an executable Go program. > > ## What does this program print? ```go package main func main() { fmt.Println(Hi! I want to be a Gopher!) } ``` * Hi! I want to be a Gopher! * It doesn't print anything * This program is incorrect *CORRECT* > **1:** It doesn't pass the message to Println wrapped between double-quotes. It should be like: fmt.Println("Hi! I want to be a Gopher") > > > **3:** It doesn't import "fmt" package. Also see #1. > > ## What does this program print? ```go package main import "fmt" func main() { fmt.Println("Hi there!") } ``` * Hi there! *CORRECT* * fmt * This program is incorrect; it imports the wrong package or there isn't a function called `Println` > **2:** import "fmt" imports the `fmt` package; so you can use its functionalities. > > > **3:** Actually, this program is correct. > >