Learning GO: 05 - Function Declaration

Hey! I am Currently learning Go Lang, and I am taking some basic Notes on my Notion and though I'd also just publish them here. They are not well thought out or well written but it's just me taking notes from time to time for my reference.

I am taking the Udemy Course by Maximilian Schwarzmüller,

Notes

Defining Functions

• all the user defined Functions are defined below the main function
• a function in Go can be defined using func keyword
• We can add parameters to the function, when adding parameters we have to define the type of the parameter

func outputText(text1 string, text2 string){
    fmt.Print()
}

• if the parameters are of same type then we can define the parameter and have the type only once, then we have to add the parameter name and at the end add the type of the parameter

func outputText(text1, text2 string) {
    fmt.Print()
}

• After that we can use it like any other function in any language

outputText("Investment Amount: ")
fmt.Scan(&investmentAmount)

func outputText(text1 string) {
    fmt.Print(text1)
}

• in Go lang, we can return multiple values from a single function
• In Go, variables are block scoped, which means any variables defined inside the function or block are scoped to that function and we can use them outside the function
• We can define the variables outside the main function or any other function to have them as global scope and then we can use them inside any function in the file.
• We can only define const and var declaration as global declaration, we cannot do this to any other declaration
• That means := syntax cannot be used in the global scope

const inflationRate = 2.5

func main() {
    var investmentAmount float64 = 1000
    var years float64
    var expectedReturn = 5.5
}

• when returning any value, we have to define the return type of the function
• If we are returning 2 values we have to wrap it into rounded parenthesis, and then define the type of specific return to its type
• with this we can define specific types to any return value func demo ()(float64, int){}

func calculateFutureValue(investmentAmount, expectedReturn, years float64) (float64, float64) {
    fv := (investmentAmount) * math.Pow(1+expectedReturn/100, float64(years))
    rfv := fv / math.Pow(1+inflationRate/100, years)
    return fv, rfv
}

• when we want to store the return values in the variable, we can have 2 variable by comma separated variable names

futureValue, futureRealValue := calculateFutureValue(investmentAmount, expectedReturn, years)