Hellow World

Sorry, its a custom for our programmer or coder or any geeks to start learning with Hellow world. So here it is. See and try to understand and at the right moment - forget it ;) !



In [23]:

    
object HelloWorld {
    def main(args: Array[String]) {
        println("Hello World")
    }
}









    Out[23]:





defined object HelloWorld

Save this above code as 'hello.scala' and run like scala hello.scala.

quick start

my fav part :)

lets learn by example. we shall explore values, variables and some crazy def variables. We shall also see what are Arrays look like and then we will define a list of numbers(range in python).



In [25]:

    
// short form
println("HelloWorld")









    



HelloWorld



In [28]:

    
// val -> value; these does not change with time. Like our mentor, teachers -> they help us guide
val a = 12
a









    Out[28]:





a: Int = 12
res27_1: Int = 12



In [31]:

    
// var -> variable; these are like blocks that help build and do wonderful stuff -> they help us build
var names = 1 to 5

println(names)









    



Range(1, 2, 3, 4, 5)






    Out[31]:





names: Range.Inclusive = Range(1, 2, 3, 4, 5)



In [32]:

    
// for loop, parsing through each variable
for(each <- names) {
  println(each)
}



In [37]:

    
var names = Array('a', 'b', 'c')

// for loop, parsing through each variable
for(each <- names) {
  println("variable item - " + each)
}









    



variable item - a
variable item - b
variable item - c






    Out[37]:





names: Array[Char] = Array('a', 'b', 'c')



In [18]:

    
var x=30
x









    Out[18]:





x: Int = 30
res17_1: Int = 30



In [4]:

    
var x=30l
x









    Out[4]:





x: Long = 30L
res3_1: Long = 30L



In [38]:

    
x += 112
x









    Out[38]:





res37_1: Long = 254L



In [39]:

    
x % 12; x / 12









    Out[39]:





res38_0: Long = 2L
res38_1: Long = 21L



In [40]:

    
x == 12; x < 12; x <= 12; x != 12; x > 13









    Out[40]:





res39_0: Boolean = false
res39_1: Boolean = false
res39_2: Boolean = false
res39_3: Boolean = true
res39_4: Boolean = true



In [41]:

    
x << 1; x >> 2









    Out[41]:





res40_0: Long = 508L
res40_1: Long = 63L



In [44]:

    
256 << 1; 256 >> 2









    Out[44]:





res43_0: Int = 512
res43_1: Int = 64



In [45]:

    
/*
Well we shall know !
*/

"hello " + "world"









    Out[45]:





res44: String = "hello world"

variables - functions



In [46]:

    
def sam = 12









    Out[46]:





defined function sam



In [47]:

    
sam * 12









    Out[47]:





res46: Int = 144

Function



In [48]:

    
def square(x: Int) = x * x









    Out[48]:





defined function square



In [49]:

    
square(12)









    Out[49]:





res48: Int = 144



In [50]:

    
square(121 + 12)









    Out[50]:





res49: Int = 17689



In [51]:

    
square(12); square(211);









    Out[51]:





res50_0: Int = 144
res50_1: Int = 44521



In [56]:

    
square(1) + 2









    Out[56]:





res55: Int = 3



In [59]:

    
def sumOfSquares(x:Int, y:Int) = square(x) + square(x)









    Out[59]:





defined function sumOfSquares



In [60]:

    
sumOfSquares(12, 12)









    Out[60]:





res59: Int = 288

conditional experessions



In [61]:

    
def abs(x: Double) = if (x > 0) x else -x









    Out[61]:





defined function abs



In [63]:

    
abs(12); abs(-12)









    Out[63]:





res62_0: Double = 12.0
res62_1: Double = 12.0



In [64]:

    
def nand(x: Boolean) = x









    Out[64]:





defined function nand



In [65]:

    
nand(true)









    Out[65]:





res64: Boolean = true



In [68]:

    
def and(x: Boolean, y: Boolean)= (x && y)

def nand(x: Boolean, y: Boolean)= !(x && y)









    Out[68]:





defined function and
defined function nand



In [69]:

    
and(true, true); and(true, false); and(false, true); and(false, false);









    Out[69]:





res68_0: Boolean = true
res68_1: Boolean = false
res68_2: Boolean = false
res68_3: Boolean = false



In [70]:

    
nand(true, true); nand(true, false); nand(false, true); nand(false, false);









    Out[70]:





res69_0: Boolean = false
res69_1: Boolean = true
res69_2: Boolean = true
res69_3: Boolean = true



In [71]:

    
def or(x: Boolean, y: Boolean) = x || y
def nor(x: Boolean, y: Boolean) = !(or(x, y))









    Out[71]:





defined function or
defined function nor



In [76]:

    
var mybools = Array(true, false)
mybools









    Out[76]:





mybools: Array[Boolean] = Array(true, false)
res75_1: Array[Boolean] = Array(true, false)



In [77]:

    
for(x <- mybools){
    for(y <- mybools){
        println(x, y, and(x, y), or(x, y));
}
}









    



(true,true,true,true)
(true,false,false,true)
(false,true,false,true)
(false,false,false,false)



In [84]:

    
var array_games = 1 to 5

for (each <- array_games) {
    println("variable -> " +  each)
}









    



variable -> 1
variable -> 2
variable -> 3
variable -> 4
variable -> 5






    Out[84]:





array_games: Range.Inclusive = Range(1, 2, 3, 4, 5)



In [85]:

    
def f(x: Int) = x + 1









    Out[85]:





defined function f



In [86]:

    
f(12)









    Out[86]:





res85: Int = 13



In [ ]: