//geometry.go
package main 

import (  
    "fmt"
    "golang-tutorial/geometry/rectangle" //importing custom package
    "log"
)
/*
 * 1. package variables
*/
var rectLen, rectWidth float64 = -6, 7 

/*
*2. init function to check if length and width are greater than zero
*/
func init() {  
    println("main package initialized")
    if rectLen < 0 {
        log.Fatal("length is less than zero")
    }
    if rectWidth < 0 {
        log.Fatal("width is less than zero")
    }
}

func main() {  
    fmt.Println("Geometrical shape properties")
    fmt.Printf("area of rectangle %.2f\n", rectangle.Area(rectLen, rectWidth))
    fmt.Printf("diagonal of the rectangle %.2f ",rectangle.Diagonal(rectLen, rectWidth))
}