Introduction to Source Code Elements

Programming and Source Code Elements

A Simple Go Demo Program

package main // specify the source file's package

import "math/rand" // import a standard package

const MaxRnd = 16 // a named constant declaration

// A function declaration
/*
 StatRandomNumbers produces a certain number of
 non-negative random integers which are less than
 MaxRnd, then counts and returns the numbers of
 small and large ones among the produced randoms.
 n specifies how many randoms to be produced.
*/
func StatRandomNumbers(n int) (int, int) {
	// Declare two variables (both as 0).
	var a, b int
	// A for-loop control flow.
	for i := 0; i < n; i++ {
		// An if-else control flow.
		if rand.Intn(MaxRnd) < MaxRnd/2 {
			a = a + 1
		} else {
			b++ // same as: b = b + 1
		}
	}
	return a, b // this function return two results
}

// "main" function is the entry function of a program.
func main() {
	var num = 100
	// Call the declared StatRandomNumbers function.
	x, y := StatRandomNumbers(num)
	// Call two built-in functions (print and println).
	print("Result: ", x, " + ", y, " = ", num, "? ")
	println(x+y == num)
}

$ go run basic-code-element-demo.go
Result: 46 + 54 = 100? true

About Line Breaks

func StatRandomNumbers(n int) (int, int)
{ // syntax error
	var a, b int
	for i := 0; i < n; i++
	{ // syntax error
		if rand.Intn(MaxRnd) < MaxRnd/2
		{ // syntax error
			a = a + 1
		} else {
			b++
		}
	}
	return a, b
}

1. they make code compilations become faster.
2. they make the coding styles written by different gophers look similar, so that it is more easily for gophers to read and understand the code written by other gophers.