Added if-else, more info in Arrays.md, Loops.md

Added tutorial for if-else statements in golang.

Added some information in Arrays.md

Added some information and using for loop as a while loop in Loops.md

Author: shrn01

tutorials/learn-golang.org/en/Arrays.md

@@ -4,18 +4,26 @@ Arrays
 ------
 Arrays are essentially storage spaces that can be filled with as much data as one would like. Variables, unlike arrays, can only contain one piece of data. Now there are some caveats. For instance, an array is syntactically created using one data type, just like variables. Yet, an array grants ease of access and far more capabilities when considering large/vast amounts of data compared to a variable(single storage space/value). 
 
+A array in golang has fixed size similar to C and C++ that we give while we define it. We can't change the size of the array dynamically while the program is running.
+
 Examples
 --------
 
+Arrays in golang are defined using the syntax,
+
+	var <name of array> [<size of array>]<type of data stored in the array>
+
+Arrays in golang are 0 indexed i.e. the index starts from 0. Let's make some arrays using the syntax given above
+
 	// An array named favNums filled with 3 integers
-	var favNums[3] int
+	var favNums [3]int
 
 	// Insert data into the array
-	// The first storage space will be assigned the value of 1.
+	// The first storage space will be assigned the value of 1. It has an index of 0.
 	favNums[0] = 1
-	// The second storage space will be assigned the value of 2.
+	// The second storage space will be assigned the value of 2. It has an index of 1.
 	favNums[1] = 2
-	// The third and final storage space will be assigned the value of 3.
+	// The third and final storage space will be assigned the value of 3. It has an index of 2.
 	favNums[2] = 3
 
 

tutorials/learn-golang.org/en/If-Else.md

@@ -0,0 +1,140 @@
+Tutorial
+--------
+
+In Golang we have if-else statements to check a condition and execute the relevant code.
+
+## if statement
+
+The if statement is used to check if a condition is met and execute the code inside the if block only if the condition is met.
+
+The general syntax is
+
+    if <condition> {
+        // Code to be executed if the condition is met.
+    }
+
+Let us write a example code to test if we need to take an umbrella based on if it's raining or not outside.
+
+    isRaining := true
+
+    if isRaining {
+        fmt.Println("It's raining, take an umbrella")
+    }
+
+## else statement
+
+If the condition in a if statement is not met then we execute the else block if it is defined.
+
+The syntax is 
+
+    if <condition> {
+        // code executes if condition is true
+    } else {
+        // code executes if condition is false
+    }
+
+One thing to remember here is the else statement should always be in the same line as the closing `}` of the if statement. 
+
+    // below code doesn't work as else is not in the same line as if's closing }
+    if <condition> {
+        // code executes if condition is true
+    } 
+    else {
+        // code executes if condition is false
+    }
+
+In the last module, we checked if it's raining and we gave a message if it is raining. But our code doesn't print anything if it is not raining. Let us fix it by adding an else statement and providing more information.
+
+    isRaining := true
+
+    if isRaining {
+        fmt.Println("It's raining, take an umbrella")
+    } else {
+        fmt.Println("It's not raining. Umbrella not needed")
+    }
+
+## Example
+Let's write an example code to check if the user's name is `John` or not
+
+    userName := "John"
+
+    // prints You are John
+    if userName == "John" {
+        fmt.Println("You are John")
+    } else {
+        fmt.Println("You are not John")
+    }
+
+    // let's try again changing the username variable
+    userName = "Mathew"
+
+    // prints You are not John
+    if userName == "John" {
+        fmt.Println("You are John")
+    } else {
+        fmt.Println("You are not John")
+    }
+
+You can cascade if statement in an else statement to check for more conditions and run the relevant code. 
+
+Now let's write some code to check if a user age is below 20 or between 20 and 60 or above 60.
+
+    userAge = 26
+
+    if userAge < 20 {
+        fmt.Println("Below 20")
+    } else if userAge >= 20 && userAge <= 60 {
+        fmt.Println("Between 20 and 60")
+    } else {
+        fmt.Println("Above 60")
+    }
+
+The if statement also provides an option to initialize a variable and test the condition within the if statement. The general syntax in this case is
+
+    if <init>;<condition> {
+        // code to execute if condition is true
+    }
+
+An example code is given below.
+
+    if userName := "Jeremy"; userName == "John" {
+        fmt.Println("You are John")
+    } else {
+        fmt.Println("You are not John")
+    }
+
+Exercise
+--------
+In a country, a person is allowed to vote if his/her age is above or equal to 18. Check the userAge variable and print `"Eligible"` if the person is eligible to vote or `"Not Eligible"` if the person is not eligible. 
+
+Tutorial Code
+-------------
+package main
+
+import "fmt"
+
+func main () {
+    userAge := 22
+
+    // Add your code here.
+}
+
+Expected Output
+---------------
+Eligible
+
+Solution
+--------
+package main
+
+import "fmt"
+
+func main () {
+    userAge := 22
+
+    if userAge >= 18 {
+        fmt.Println("Eligible")
+    } else {
+        fmt.Println("Not Eligible")
+    }
+}

tutorials/learn-golang.org/en/Loops.md

@@ -19,6 +19,8 @@ The loop will stop iterating once the boolean condition evaluates to false.
 Examples
 --------
 
+The following code prints numbers from 1 to 9.
+
 	package main
 
 	import "fmt"
@@ -29,10 +31,25 @@ Examples
 		}
 	}
 
+You can omit the init and post statement in the `for` loop to get a while loop. The below loop works like a while loop
+
+	package main
+
+	import "fmt"
+
+	func main() {
+		i := 0
+
+		for i < 10 {
+			fmt.Println(i)
+			i++
+		}
+	}
+	
 
 Exercise
 --------
-Find the sum of numbers from 1 to 100
+Find the sum of numbers from 1 to 100 using a for loop
 
 Tutorial Code
 -------------

tutorials/learn-golang.org/en/Welcome.md

@@ -13,6 +13,7 @@ learn-golang.org is still under construction - If you wish to contribute tutoria
 - [[Hello, World!]]
 - [[Variables]]
 - [[Arrays]]
+- [[If-Else]]
 - [[Loops]]
 
 ### Contributing Tutorials