Initial commit

08-numbers-and-strings/01-numbers/01-arithmetic-operators/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// when an integer and a float value used together
+	// in an expression, the result always becomes
+	// a float value
+	fmt.Println(8 * -4.0) // -32.0 not -32
+
+	// two integer values result in an integer value
+	fmt.Println(-4 / 2)
+
+	// remainder operator
+	// it can only used with integers
+	fmt.Println(5 % 2)
+	// fmt.Println(5.0 % 2) // wrong
+
+	// addition operators
+	fmt.Println(1 + 2.5)
+	fmt.Println(2 - 3)
+
+	// negation operator
+	fmt.Println(-(-2))
+	fmt.Println(- -2) // this also works
+}

08-numbers-and-strings/01-numbers/01-arithmetic-operators/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	var (
+		myAge   = 30
+		yourAge = 35
+		average float64
+	)
+
+	average = float64(myAge+yourAge) / 2
+
+	fmt.Println(average)
+}

08-numbers-and-strings/01-numbers/01-arithmetic-operators/03-float-inaccuracy/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	ratio := 1.0 / 10.0
+
+	// after 10 operations
+	// the inaccuracy is clear
+	//
+	// BTW, don't mind about this loop syntax for now
+	// I'm going to explain it afterwards
+	for range [...]int{10: 0} {
+		ratio += 1.0 / 10.0
+	}
+
+	fmt.Printf("%.60f", ratio)
+}

08-numbers-and-strings/01-numbers/01-arithmetic-operators/03-float-inaccuracy/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// Go compiler sees these numbers as integers,
+	//   since, there are no fractional parts in
+	//   integer values,
+	// So, the result becomes 1 instead of 1.5
+
+	// So, ratio variable here is an int variable,
+	//   it's because, 3 divided by 2 results
+	//   in an integer.
+
+	ratio := 3 / 2
+
+	fmt.Printf("%d", ratio)
+}

08-numbers-and-strings/01-numbers/01-arithmetic-operators/03-float-inaccuracy/03/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// When you use a float value with an integer
+	// in a calculation,
+	// the result always becomes a float.
+
+	ratio := 3.0 / 2
+
+	// OR:
+	// ratio = 3 / 2.0
+
+	// OR - if 3 is inside an int variable:
+	// n := 3
+	// ratio = float64(n) / 2
+
+	fmt.Printf("%f", ratio)
+}

08-numbers-and-strings/01-numbers/02-arithmetic-operators-examples/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("sum :", 3+2)   // sum - int
+	fmt.Println("sum :", 2+3.5) // sum - float64
+	fmt.Println("dif :", 3-1)   // difference - int
+	fmt.Println("dif :", 3-0.5) // difference - float64
+	fmt.Println("prod:", 4*5)   // product - int
+	fmt.Println("prod:", 5*2.5) // product - float64
+	fmt.Println("quot:", 8/2)   // quotient - int
+	fmt.Println("quot:", 8/1.5) // quotient - float64
+
+	// remainder is only for integers
+	fmt.Println("rem :", 8%3)
+	// fmt.Println("rem:", 8.0%3) // error
+
+	// you can do this
+	// since the fractional part of a float is zero
+	f := 8.0
+	fmt.Println("rem :", int(f)%3)
+}

08-numbers-and-strings/01-numbers/02-arithmetic-operators-examples/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// what's the value of the ratio?
+	// 3 / 2 = 1.5?
+	var ratio float64 = 3 / 2
+	fmt.Println(ratio)
+
+	// explain
+	// above expression equals to this:
+	ratio = float64(int(3) / int(2))
+	fmt.Println(ratio)
+
+	// how to fix it?
+	//
+	// remember, when one of the values is a float value
+	// the result becomes a float
+	ratio = float64(3) / 2
+	fmt.Println(ratio)
+
+	// or
+	ratio = 3.0 / 2
+	fmt.Println(ratio)
+}

08-numbers-and-strings/01-numbers/03-precedence/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println(
+		2+2*4/2,
+		2+((2*4)/2), // same as above
+	)
+
+	fmt.Println(
+		1+4-2,
+		(1+4)-2, // same as above
+	)
+
+	fmt.Println(
+		(2+2)*4/2,
+		(2+2)*(4/2), // same as above
+	)
+}

08-numbers-and-strings/01-numbers/03-precedence/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	n, m := 1, 5
+
+	fmt.Println(2 + 1*m/n)
+	fmt.Println(2 + ((1 * m) / n)) // same as above
+
+	// let's change the precedence using parentheses
+	fmt.Println(((2 + 1) * m) / n)
+}

08-numbers-and-strings/01-numbers/03-precedence/03/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+func main() {
+	// // Precedence: Order of expressions
+	// // Multiplication operators runs first: * and /
+
+	// fmt.Println(
+	// 	1 + 5 - 3*10/2,
+	// )
+
+	// // 3 * 10 = 30
+	// // 30 / 2 = 15
+	// // 1 + 5  = 6
+	// // 6 - 15 = -9
+
+	// // **** TIP ****
+	// // Use parentheses to change the order of evaluation.
+	// // First, (1+5-3), then (10/2) will be calculated.
+
+	// fmt.Println(
+	// 	(1 + 5 - 3) * (10 / 2),
+	// )
+}

08-numbers-and-strings/01-numbers/03-precedence/04/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	celsius := 35.
+
+	// Wrong formula  :  9*celsius + 160  / 5
+	// Correct formula: (9*celsius + 160) / 5
+	fahrenheit := (9*celsius + 160) / 5
+
+	fmt.Printf("%g ºC is %g ºF\n", celsius, fahrenheit)
+}

08-numbers-and-strings/01-numbers/04-incdec-statement/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	var n int
+
+	// ALTERNATIVES:
+	// n = n + 1
+	// n += 1
+
+	// BETTER:
+	n++
+
+	fmt.Println(n)
+}

08-numbers-and-strings/01-numbers/04-incdec-statement/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	n := 10
+
+	// ALTERNATIVES:
+	// n = n - 1
+	// n -= 1
+
+	// BETTER:
+	n--
+
+	fmt.Println(n)
+}

08-numbers-and-strings/01-numbers/04-incdec-statement/03/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// incdec is a statement
+
+func main() {
+	var counter int
+
+	// following "statements" are correct:
+
+	counter++ // 1
+	counter++ // 2
+	counter++ // 3
+	counter-- // 2
+	fmt.Printf("There are %d line(s) in the file\n",
+		counter)
+
+	// the following "expressions" are incorrect:
+
+	// counter = 5+counter--
+	// counter = ++counter + counter--
+}

08-numbers-and-strings/01-numbers/05-assignment-operations/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	width, height := 5., 12.
+
+	// calculates the area of a rectangle
+	area := width * height
+	fmt.Printf("%gx%g=%g\n", width, height, area)
+
+	area = area - 10 // decreases area by 10
+	area = area + 10 // increases area by 10
+	area = area * 2  // doubles the area
+	area = area / 2  // divides the area by 2
+	fmt.Printf("area=%g\n", area)
+
+	// // ASSIGNMENT OPERATIONS
+	area -= 10 // decreases area by 10
+	area += 10 // increases area by 10
+	area *= 2  // doubles the area
+	area /= 2  // divides the area by 2
+	fmt.Printf("area=%g\n", area)
+
+	// finds the remainder of area variable
+	// since: area is float, this won't work:
+	// area %= 7
+
+	// this works
+	area = float64(int(area) % 7)
+	fmt.Printf("area=%g\n", area)
+}

08-numbers-and-strings/01-numbers/06-project-feet-to-meters/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+)
+
+func main() {
+	arg := os.Args[1]
+
+	// feet is a float64 now
+	feet, _ := strconv.ParseFloat(arg, 64)
+
+	meters := feet * 0.3048
+
+	fmt.Printf("%f feet is %f meters.\n", feet, meters)
+
+	// pretty print it:
+
+	// fmt.Printf("%g feet is %g meters.\n", feet, meters)
+}

08-numbers-and-strings/01-numbers/exercises/01/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+// ---------------------------------------------------------
+// EXERCISE
+//  1. Print the sum of 50 and 25
+//  2. Print the difference of 50 and 15.5
+//  3. Print the product of 50 and 0.5
+//  4. Print the quotient of 50 and 0.5
+//  5. Print the remainder of 25 and 3
+//  6. Print the negation of `5 + 2`
+//
+// EXPECTED OUTPUT
+//  75
+//  34.5
+//  25
+//  100
+//  1
+//  -7
+// ---------------------------------------------------------
+
+func main() {
+	// ADD YOUR CODE BELOW
+	// USE `fmt.Println` for each question
+
+	// DO NOT TOUCH THIS
+	// fmt.Println(x)
+}

08-numbers-and-strings/01-numbers/exercises/01/solution/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println(50 + 25)
+	fmt.Println(50 - 15.5)
+	fmt.Println(50 * 0.5)
+	fmt.Println(50 / 0.5)
+	fmt.Println(25 % 3)
+	fmt.Println(-(5 + 2))
+}

08-numbers-and-strings/01-numbers/exercises/02/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// ---------------------------------------------------------
+// EXERCISE
+//  Fix the program to print 2.5 instead of 2
+//
+// EXPECTED OUTPUT
+//  2.5
+// ---------------------------------------------------------
+
+func main() {
+	x := 5 / 2
+	fmt.Println(x)
+}

08-numbers-and-strings/01-numbers/exercises/02/solution/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// Below solutions are correct:
+	x := 5. / 2
+	// x := 5 / 2.
+	// x := float64(5) / 2
+	// x := 5 / float64(2)
+
+	fmt.Println(x)
+}

08-numbers-and-strings/01-numbers/exercises/03/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// ---------------------------------------------------------
+// EXERCISE
+//  Change the expressions to produce the expected outputs
+//
+// RESTRICTION
+//  Use parentheses to change the precedence
+// ---------------------------------------------------------
+
+func main() {
+	// This expression should print 20
+	fmt.Println(10 + 5 - 5 - 10)
+
+	// This expression should print -16
+	fmt.Println(-10 + 0.5 - 1 + 5.5)
+
+	// This expression should print -25
+	fmt.Println(5 + 10*2 - 5)
+
+	// This expression should print 0.5
+	fmt.Println(0.5*2 - 1)
+
+	// This expression should print 24
+	fmt.Println(3 + 1/2*10 + 4)
+
+	// This expression should print 15
+	fmt.Println(10 / 2 * 10 % 7)
+}

08-numbers-and-strings/01-numbers/exercises/03/solution/main.go

@@ -0,0 +1,30 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	// 10 + 5 - 5 - 10
+	fmt.Println(10 + 5 - (5 - 10))
+
+	// -10 + 0.5 - 1 + 5.5
+	fmt.Println(-10 + 0.5 - (1 + 5.5))
+
+	// 5 + 10*2 - 5
+	fmt.Println(5 + 10*(2-5))
+
+	// 0.5*2 - 1
+	fmt.Println(0.5 * (2 - 1))
+
+	// 3 + 1/2*10 + 4
+	fmt.Println((3+1)/2*10 + 4)
+
+	// 10 / 2 * 10 % 7
+	fmt.Println(10 / 2 * (10 % 7))
+}

08-numbers-and-strings/01-numbers/exercises/04/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+// ---------------------------------------------------------
+// EXERCISE
+//  1. Increase the `counter` 5 times
+//  2. Decrease the `factor` 2 times
+//  3. Print the product of counter and factor
+//
+// RESTRICTION
+//  Use only the incdec statements
+//
+// EXPECTED OUTPUT
+//  -75
+// ---------------------------------------------------------
+
+func main() {
+	// DO NOT TOUCH THIS
+	counter, factor := 45, 0.5
+
+	// TYPE YOUR CODE BELOW
+	// ...
+
+	// LASTLY: REMOVE THE CODE BELOW
+	_, _ = counter, factor
+}

08-numbers-and-strings/01-numbers/exercises/04/solution/main.go

@@ -0,0 +1,25 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	counter, factor := 45, 0.5
+
+	counter++
+	counter++
+	counter++
+	counter++
+	counter++
+
+	factor--
+	factor--
+
+	fmt.Println(float64(counter) * factor)
+}

08-numbers-and-strings/01-numbers/exercises/05/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// ---------------------------------------------------------
+// EXERCISE
+//  1. Write the simplest line of code to increase
+//     the counter variable by 1.
+//
+//  2. Write the simplest line of code to decrease
+//     the counter variable by 1.
+//
+//  3. Write the simplest line of code to increase
+//     the counter variable by 5.
+//
+//  4. Write the simplest line of code to multiply
+//     the counter variable by 10.
+//
+//  5. Write the simplest line of code to divide
+//     the counter variable by 5.
+//
+// EXPECTED OUTPUT
+//  10
+// ---------------------------------------------------------
+
+func main() {
+	// DO NOT CHANGE THE CODE BELOW
+	var counter int
+
+	// TYPE YOUR CODE HERE
+
+	// DO NOT CHANGE THE CODE BELOW
+	fmt.Println(counter)
+}

08-numbers-and-strings/01-numbers/exercises/05/solution/main.go

@@ -0,0 +1,23 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	var counter int
+
+	counter++
+	counter--
+
+	counter += 5
+	counter *= 10
+	counter /= 5
+
+	fmt.Println(counter)
+}

08-numbers-and-strings/01-numbers/exercises/06/main.go

@@ -0,0 +1,35 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// ---------------------------------------------------------
+// EXERCISE
+//  Simplify the code (refactor)
+//
+// RESTRICTION
+//  Use only the incdec and assignment operations
+//
+// EXPECTED OUTPUT
+//  3
+// ---------------------------------------------------------
+
+func main() {
+	width, height := 10, 2
+
+	width = width + 1
+	width = width + height
+	width = width - 1
+	width = width - height
+	width = width * 20
+	width = width / 25
+	width = width % 5
+
+	fmt.Println(width)
+}

08-numbers-and-strings/01-numbers/exercises/06/solution/main.go

@@ -0,0 +1,24 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	width, height := 10, 2
+
+	width++
+	width += height
+	width--
+	width -= height
+	width *= 20
+	width /= 25
+	width %= 5
+
+	fmt.Println(width)
+}

08-numbers-and-strings/01-numbers/exercises/07-capstone1/main.go

@@ -0,0 +1,45 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+)
+
+// ---------------------------------------------------------
+// EXERCISE
+//  Calculate the area of a circle from the given radius
+//
+// CIRCLE AREA FORMULA
+//  area = πr²
+//  https://en.wikipedia.org/wiki/Area#Circles
+//
+// HINT
+//  For PI you can use `math.Pi`
+//
+// EXPECTED OUTPUT
+//  314.1592653589793
+//
+// BONUS EXERCISE!
+//   1. Print the area as 314.16
+//   2. To do that you need to use the correct Printf verb :)
+//      Instead of `%g` verb below.
+// ---------------------------------------------------------
+
+func main() {
+	var (
+		radius = 10.
+		area   float64
+	)
+
+	// ADD YOUR CODE HERE
+	// ...
+
+	// DO NOT TOUCH THIS
+	fmt.Printf("radius: %g -> area: %g\n", radius, area)
+}

08-numbers-and-strings/01-numbers/exercises/07-capstone1/solution/main.go

@@ -0,0 +1,29 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func main() {
+	var (
+		radius = 10.
+		area   float64
+	)
+
+	area = math.Pi * radius * radius
+
+	fmt.Printf("radius: %g -> area: %.2f\n",
+		radius, area)
+
+	// ALTERNATIVE:
+	// math.Pow calculates the power of a float number
+	// area = math.Pi * math.Pow(radius, 2)
+}

08-numbers-and-strings/01-numbers/exercises/08-capstone2/main.go

@@ -0,0 +1,41 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+)
+
+// ---------------------------------------------------------
+// EXERCISE
+//  1. Get the radius from the command-line
+//  2. Convert it to a float64
+//  3. Calculate the surface area of a sphere
+//
+// SPHERE SURFACE AREA FORMULA
+//  area = 4πr²
+//  https://en.wikipedia.org/wiki/Sphere#Surface_area
+//
+// RESTRICTION
+//  Use `math.Pow` to calculate the area
+//  Read its documentation to see how it works.
+//  https://golang.org/pkg/math/#Pow
+//
+// EXPECTED OUTPUT
+//  1256.64
+// ---------------------------------------------------------
+
+func main() {
+	var radius, area float64
+
+	// ADD YOUR CODE HERE
+	// ...
+
+	// DO NOT TOUCH THIS
+	fmt.Printf("radius: %g -> area: %.2f\n", radius, area)
+}

08-numbers-and-strings/01-numbers/exercises/08-capstone2/solution/main.go

@@ -0,0 +1,26 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+)
+
+func main() {
+	var radius, area float64
+
+	radius, _ = strconv.ParseFloat(os.Args[1], 64)
+
+	area = 4 * math.Pi * math.Pow(radius, 2)
+
+	fmt.Printf("radius: %g -> area: %.2f\n",
+		radius, area)
+}

08-numbers-and-strings/01-numbers/exercises/09-capstone3/main.go

@@ -0,0 +1,38 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+)
+
+// ---------------------------------------------------------
+// EXERCISE
+//  1. Get the radius from the command-line
+//  2. Convert it to a float64
+//  3. Calculate the volume of a sphere
+//
+// SPHERE VOLUME FORMULA
+//  https://en.wikipedia.org/wiki/Sphere#Enclosed_volume
+//
+// RESTRICTION
+//  Use `math.Pow` to calculate the volume
+//
+// EXPECTED OUTPUT
+//  4188.79
+// ---------------------------------------------------------
+
+func main() {
+	var radius, vol float64
+
+	// ADD YOUR CODE HERE
+	// ...
+
+	// DO NOT TOUCH THIS
+	fmt.Printf("radius: %g -> volume: %.2f\n", radius, vol)
+}

08-numbers-and-strings/01-numbers/exercises/09-capstone3/solution/main.go

@@ -0,0 +1,25 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+)
+
+func main() {
+	var radius, vol float64
+
+	radius, _ = strconv.ParseFloat(os.Args[1], 64)
+
+	vol = (4 * math.Pi * math.Pow(radius, 3)) / 3
+
+	fmt.Printf("radius: %g -> volume: %.2f\n", radius, vol)
+}

08-numbers-and-strings/01-numbers/questions/01-arithmetic-operators.md

@@ -0,0 +1,95 @@
+## Which group of operators below is arithmetic operators?
+1. **, /, ^, !, ++, --
+2. *, /, %, +, - *CORRECT*
+3. &, |, +, -, /
+
+
+## Which value below you can use with a remainder operator?
+1. 3.54
+2. true
+3. 57 *CORRECT*
+4. "Try Me!"
+
+> 4. Nice Try. But, that's not right. Sorry.
+> 3. That's right. The remainder operator only works on integer values.
+
+
+## What's the result of this expression?
+```go
+8 % 3
+```
+1. 4
+2. 2
+3. 0
+4. 1 *CORRECT*
+
+
+## What's the result of this expression?
+```go
+-(3 * -2)
+```
+1. -6
+2. -1
+3. 0
+4. 6 *CORRECT*
+
+
+## What's the result of this expression?
+```go
+var degree float64 = 10 / 4
+```
+1. 2.5
+2. 2.49
+3. 2 *CORRECT*
+4. 0
+
+> 3. That's right. An integer value cannot contain fractional parts.
+
+
+## What's the result of this expression?
+```go
+var degree float64 = 3. / 2
+```
+1. 1.5 *CORRECT*
+2. 1.49
+3. 1
+4. 0
+
+> 1. That's right. `3.` makes the whole expression a float value.
+
+
+## What's the type of the `x` variable?
+```go
+x := 5 * 2.
+```
+1. int
+2. float64 *CORRECT*
+3. bool
+4. string
+
+> 1. Look closely to 2 there.
+> 2. Why? Because, `2.` there makes the expressions a float value. Cool.
+> 3. Oh, come on! Life is not always true and false.
+> 4. I can't see any double-quotes or back-quotes, can you?
+
+
+## What's the type of the `x` variable?
+```go
+x := 5 * -(2)
+```
+1. int *CORRECT*
+2. float64
+3. bool
+4. string
+
+> 1. Why? Because, there only integer numbers.
+> 2. I can't see any fractional parts there, can you?
+> 3. Oh, come on! Life is not always true and false.
+> 4. I can't see any double-quotes or back-quotes, can you?
+
+
+## Which kind of values can result in inaccurate calculations?
+1. integers
+2. floats *CORRECT*
+3. bools
+4. strings

08-numbers-and-strings/01-numbers/questions/02-precedence.md

@@ -0,0 +1,44 @@
+## What's the result of the expression?
+```go
+5 - 2 * 5 + 7
+```
+1. 2 *CORRECT*
+2. 22
+3. -19
+4. 36
+5. -12
+
+
+## What's the result of the expression?
+```go
+5 - (2 * 5) + 7
+```
+1. 2
+2. 22 *CORRECT*
+3. -19
+4. 36
+5. -12
+
+
+## What's the result of the expression?
+```go
+5 - 2 * (5 + 7)
+```
+1. 2
+2. 22
+3. -19 *CORRECT*
+4. 36
+5. -12
+
+
+## What's the result of the expression?
+```go
+5. -(2 * 5 + 7)
+```
+1. 2
+2. 22
+3. -19
+4. -12
+5. -12.0 *CORRECT*
+
+> 4. You're close but remember! The result of an expression with floats and integers is always a float.

08-numbers-and-strings/01-numbers/questions/03-assignment-operations.md

@@ -0,0 +1,98 @@
+## Which expression increases `n` by 1?
+```go
+var n float64
+```
+1. `n = +1`
+2. `n = n++`
+3. `n = n + 1` *CORRECT*
+4. `++n`
+
+> 1. This just assigns 1 to n.
+> 2. IncDec statement can't be used as an operator.
+> 4. Go doesn't support prefix incdec notation.
+
+
+## Which expression decreases `n` by 1?
+```go
+var n int
+```
+1. `n = -1`
+2. `n = n--`
+3. `n = n - 1` *CORRECT*
+4. `--n`
+
+> 1. This just assigns -1 to n.
+> 2. IncDec statement can't be used as an operator.
+> 4. Go doesn't support prefix incdec notation.
+
+
+## Which code below equals to `n = n + 1`?
+1. `n++` *CORRECT*
+2. `n = n++`
+3. `++n`
+4. `n = n ++ 1`
+
+> 2. IncDec statement can't be used as an operator.
+> 3. Go doesn't support prefix incdec notation.
+> 4. What's that? ++?
+
+
+## Which code below equals to `n = n + 1`?
+1. `n = n++`
+2. `n += 1` *CORRECT*
+3. `++n`
+4. `n = n ++ 1`
+
+> 1. IncDec statement can't be used as an operator.
+> 3. Go doesn't support prefix incdec notation.
+> 4. What's that? ++?
+
+
+## Which code below equals to `n -= 1`?
+1. `n = n--`
+2. `n += 1--`
+3. `n--` *CORRECT*
+4. `--n`
+
+> 1. IncDec statement can't be used as an operator.
+> 2. IncDec statement can't be used as an operator. And also, you can't use it with `1--`. The value should be addressable. You're going to learn what that means soon.
+> 4. Go doesn't support prefix incdec notation.
+
+
+## Which code below divides the `length` by 10?
+1. `length = length // 10`
+2. `length /= 10` *CORRECT*
+3. `length //= 10`
+
+> 1. What's that? `//`?
+> 2. That's right. This equals to: `length = length / 10`
+> 3. What's that? `//=`?
+
+
+## Which code below equals to `x = x % 2`?
+1. `x = x / 2`
+2. `x =% x`
+3. `x %= x` *CORRECT*
+
+> 1. This is a division. You need to use the remainder operator.
+> 2. Close... But, the `%` operator is on the wrong side of the assignment.
+
+
+## Which function below converts a string value into a float value?
+1. `fmtconv.ToFloat`
+2. `conv.ParseFloat`
+3. `strconv.ParseFloat` *CORRECT*
+4. `strconv.ToFloat`
+
+
+## Which code is correct?
+If you don't remember it, this its function signature:
+```go
+func ParseFloat(s string, bitSize int) (float64, error)
+```
+1. `strconv.ParseFloat("10", 128)`
+2. `strconv.ParseFloat("10", 64)` *CORRECT*
+3. `strconv.ParseFloat("10", "64")`
+4. `strconv.ParseFloat(10, 64)`
+
+> 1. There are no 128-bit floating point values in Go (Actually there are, but they only belong to the compile-time).