package main

import (
	"fmt"
	// "strconv"
	// "math"
	// "reflect"
	// "math"
)

func basicLoop()  {
	for i := 0; i < 5; i++ {
		fmt.Printf("Number: %v\n", i)
	}
}


func everyOther()  {
	for i := 0; i < 5; i = i + 2 {
		fmt.Printf("Number: %v\n", i)
	}
}

func loopOverTwoVariables()  {
	for i, j := 0, 0; i < 5; i, j = i + 1, j + 3 {
		fmt.Printf("i: %v, j: %v\n", i, j)
	} 
}

func play()  {
	for i:= 0; i < 5; i++ {
		fmt.Printf("Number: %v\n", i)
		if i%2 == 0 {
			i /= 2
		} else {
			i = 2*i + 1
		}
	}
}


func initializerAtSomeOtherPlace()  {
	i := 0
	for ; i < 5; i++ {
		fmt.Printf("Number: %v\n", i)
	}
}

func pythonLike()  {
	i := 0
	// for i < 5 {   <- works just fine withour semicolons
	for ; i < 5 ; {
		fmt.Printf("Number: %v\n", i)
		i++
	} 		
}

func infiniteForLoop()  {
	i := 0
	for {
		fmt.Printf("Number: %v\n", i)
		i++
	}
}


func infiniteForLoopWithBreak()  {
	i := 0
	for {
		fmt.Printf("Number: %v\n", i)
		i++
		if i == 5 {
			fmt.Printf("Breaking from Infinite Loop! number: %v\n", i)
			break
		}
	}
}


func forLoopWithContinueKeyWork()  {
	for i := 0; i < 10; i ++ {
		if i%2 == 0 {
			// the keyword "continue" is a special keyword
			// and if this condition above is true that we 
			// stop here and don't go and print anything !!!
			// we sort of continuing back to main loop
			continue
		}
		fmt.Printf("Number: %v\n", i)
	}
}

func nestedForLoop()  {
	for i := 1; i <= 3; i++ {
		for j := 1; j <=4; j++ {
			fmt.Printf("Multiply %v(i) * %v(j) = %v\n", i, j, i*j)
		}
	}
}


func breakOutOfNestedForLoop()  {
// This "label" below "tells to" the "break" keyword 
// which loop to exit!!! Please notice that if this label not used
// only inner most loop would be exited
Labelloop:
	for i := 1; i <= 3; i++ {
		for j := 1; j <=4; j++ {
			fmt.Printf("Multiply %v(i) * %v(j) = %v\n", i, j, i*j)
			if i * j >= 3 {
				fmt.Printf("Breaking out of nested for loop because of condition based on label!!!\n")
				break Labelloop
			}
		}
	}
}


func collectionForLoop()  {
	s := []int{1, 2, 3}
	fmt.Printf("Element: %v\n", s)	 
	fmt.Println("")
	for k, v := range s {
		fmt.Printf("Element: %v(k): %v(v)\n", k, v)	 
	}
	fmt.Println("")
	// maps
	statePopulation := make(map[string]int)
    statePopulation = map[string]int{
        "California": 2341232,
        "Texas": 3341232,
        "Florida": 4341232,
        "New York": 5341232,
        "Illinois": 6341232,
        "Ohio": 7341232,
	}
	
	fmt.Println("")
	for k,v := range statePopulation {
		fmt.Printf("Element: %v(k): %v(v)\n", k, v)	 
	}

	fmt.Println()
	//  if we only care for "keys"
	for k := range statePopulation {
		fmt.Printf("Element: %v(k)\n", k)	 
	}

	fmt.Println("")
	//  if we only care for "values"
	for _, v := range statePopulation {
		fmt.Printf("Element: %v(v)\n", v)	 
	}
	fmt.Println("")
	// strings
	st := "hello Go!"
	for k, v := range st {
		fmt.Printf("Element: %v(k): %v(v), %v(v) \n", k, v, string(v))	 
	}


}

func main() {
	// basicLoop()
	// everyOther()
	// loopOverTwoVariables()
	// play()
	// initializerAtSomeOtherPlace()
	// pythonLike()
	// infiniteForLoop()
	// infiniteForLoopWithBreak()
	// forLoopWithContinueKeyWork()
	// nestedForLoop()
	// breakOutOfNestedForLoop()
	collectionForLoop()
}