06_math_operators.go

package main

import (
	"fmt"
	"math"
	"math/big" // this is how we can add nested packages
)

func main() {
	//implicitConvert()
	//bigSum()
	circleRadius()
}

func implicitConvert() {

	// Numeric types in Go doesn't implicitly convert numeric types
	// Example: You can't add an int to a float without explicit conversion

	var int1 int = 5
	var float1 float64 = 42
	sum := float64(int1) + float1
	fmt.Printf("Sum: %v, Type: %T", sum, sum)

}

func bigSum() {

	// declares 3 variables of the same type and setting
	// all of their values in a single statement
	i1, i2, i3 := 12, 45, 68
	intSum := i1 + i2 + i3
	fmt.Println("Integer sum:", intSum)

	f1, f2, f3 := 23.5, 65.1, 76.3
	floatSum := f1 + f2 + f3
	// with floating point numbers you might not get the precision you hope for
	fmt.Println("Float sum:", floatSum)

	// use big number types to execute math operations with precision
	var b1, b2, b3, bigSum big.Float
	b1.SetFloat64(23.5)
	b2.SetFloat64(65.1)
	b3.SetFloat64(76.3)

	// & operator is the address of operator
	// it takes the address of b1 and b2 and passes to the Add function
	// the first add call takes the total of b1 and b2 and assigns it to the bigSum
	// the second add call takes the total of bigSum and b3 and assigns it to the bigSum again
	bigSum.Add(&b1, &b2).Add(&bigSum, &b3)
	fmt.Printf("BigSum = %g\n", &bigSum) // ?? for some reason arbitrary-precision arithmetic cannot handle this
}

// The math package also has a whole bunch of functions
// and constants that can help you with your mathematical
// operations
func circleRadius() {

	circleRadius := 15.5
	circumference := circleRadius * math.Pi
	fmt.Printf("Circumference: %.2f\n", circumference)

}