Initial commit

13-loops/exercises/01-loops/01-sum-the-numbers/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: Sum the numbers
+//
+//  1. By using a loop, sum the numbers between 1 and 10.
+//  2. Print the sum.
+//
+// EXPECTED OUTPUT
+//  Sum: 55
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/01-sum-the-numbers/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() {
+	var sum int
+	for i := 1; i <= 10; i++ {
+		sum += i
+	}
+	fmt.Println("Sum:", sum)
+}

13-loops/exercises/01-loops/02-sum-the-numbers-verbose/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: Sum the numbers verbose edition
+//
+//  By using a loop, sum the numbers between 1 and 10.
+//
+// HINT
+//  1. For printing it as in the expected output, use Print
+//     and Printf functions. They don't print a newline
+//     automatically (unlike a Println).
+//
+//  2. Also, you need to use an if statement to prevent
+//     printing the last plus sign.
+//
+// EXPECTED OUTPUT
+//    1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/02-sum-the-numbers-verbose/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() {
+	const min, max = 1, 10
+
+	var sum int
+	for i := min; i <= max; i++ {
+		sum += i
+
+		fmt.Print(i)
+		if i != max {
+			fmt.Print(" + ")
+		}
+	}
+	fmt.Printf(" = %d\n", sum)
+}

13-loops/exercises/01-loops/03-sum-up-to-n/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: Sum up to N
+//
+//  1. Get two numbers from the command-line: min and max
+//  2. Convert them to integers (using Atoi)
+//  3. By using a loop, sum the numbers between min and max
+//
+// RESTRICTIONS
+//  1. Be sure to handle the errors. So, if a user doesn't
+//     pass enough arguments or she passes non-numerics,
+//     then warn the user and exit from the program.
+//
+//  2. Also, check that, min < max.
+//
+// HINT
+//  For converting the numbers, you can use `strconv.Atoi`.
+//
+// EXPECTED OUTPUT
+//  Let's suppose that the user runs it like this:
+//
+//    go run main.go 1 10
+//
+//  Then it should print:
+//
+//    1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 = 55
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/03-sum-up-to-n/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"
+	"os"
+	"strconv"
+)
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("gimme two numbers")
+		return
+	}
+
+	min, err1 := strconv.Atoi(os.Args[1])
+	max, err2 := strconv.Atoi(os.Args[2])
+	if err1 != nil || err2 != nil || min >= max {
+		fmt.Println("wrong numbers")
+		return
+	}
+
+	var sum int
+	for i := min; i <= max; i++ {
+		sum += i
+
+		fmt.Print(i)
+		if i != max {
+			fmt.Print(" + ")
+		}
+	}
+	fmt.Printf(" = %d\n", sum)
+}

13-loops/exercises/01-loops/04-only-evens/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: Only evens
+//
+//  1. Extend the "Sum up to N" exercise
+//  2. Sum only the even numbers
+//
+// RESTRICTIONS
+//  Skip odd numbers using the `continue` statement
+//
+// EXPECTED OUTPUT
+//  Let's suppose that the user runs it like this:
+//
+//    go run main.go 1 10
+//
+//  Then it should print:
+//
+//    2 + 4 + 6 + 8 + 10 = 30
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/04-only-evens/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"
+	"os"
+	"strconv"
+)
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("gimme two numbers")
+		return
+	}
+
+	min, err1 := strconv.Atoi(os.Args[1])
+	max, err2 := strconv.Atoi(os.Args[2])
+	if err1 != nil || err2 != nil || min >= max {
+		fmt.Println("wrong numbers")
+		return
+	}
+
+	var sum int
+	for i := min; i <= max; i++ {
+		if i%2 != 0 {
+			continue
+		}
+		sum += i
+
+		fmt.Print(i)
+		if i != max {
+			fmt.Print(" + ")
+		}
+	}
+	fmt.Printf(" = %d\n", sum)
+}

13-loops/exercises/01-loops/05-break-up/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: Break up
+//
+//  1. Extend the "Only Evens" exercise
+//  2. This time, use an infinite loop.
+//  3. Break the loop when it reaches to the `max`.
+//
+// RESTRICTIONS
+//  You should use the `break` statement once.
+//
+// HINT
+//  Do not forget incrementing the `i` before the `continue`
+//  statement and at the end of the loop.
+//
+// EXPECTED OUTPUT
+//    go run main.go 1 10
+//    2 + 4 + 6 + 8 + 10 = 30
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/05-break-up/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"
+	"os"
+	"strconv"
+)
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("gimme two numbers")
+		return
+	}
+
+	min, err1 := strconv.Atoi(os.Args[1])
+	max, err2 := strconv.Atoi(os.Args[2])
+	if err1 != nil || err2 != nil || min >= max {
+		fmt.Println("wrong numbers")
+		return
+	}
+
+	var (
+		i   = min
+		sum int
+	)
+
+	for {
+		if i%2 != 0 {
+			i++
+			continue
+		}
+		sum += i
+
+		fmt.Print(i)
+		if i != max {
+			fmt.Print(" + ")
+		} else {
+			break
+		}
+		i++
+	}
+	fmt.Printf(" = %d\n", sum)
+}

13-loops/exercises/01-loops/06-infinite-kill/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: Infinite Kill
+//
+//  1. Create an infinite loop
+//  2. On each step of the loop print a random character.
+//  3. And, sleep for 250 milliseconds.
+//  4. Run the program and wait a couple of seconds
+//     then kill it using CTRL+C keys
+//
+// RESTRICTIONS
+//  1. Print one of those characters randomly: \ / |
+//  2. Before printing a character print also this
+//     escape sequence: \r
+//
+//     Like this: "\r/", or this: "\r|", and so on...
+//
+// HINTS
+//  1. Use `time.Sleep` to sleep.
+//  2. You should pass a `time.Duration` value to it.
+//  3. Check out the Go online documentation for the
+//     `Millisecond` constant.
+//  4. When printing, do not use a newline! Or a Println!
+//     Use Print or Printf instead.
+//
+// NOTE
+//  If this exercise is hard for you now, wait until the
+//  lucky number lecture. Even then so, then just skip it.
+//
+//  You can return back to it afterwards.
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/06-infinite-kill/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"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	for {
+		var c string
+
+		switch rand.Intn(3) {
+		case 0:
+			c = "\\"
+		case 1:
+			c = "/"
+		case 2:
+			c = "|"
+		}
+		fmt.Printf("\r%s", c)
+		time.Sleep(time.Millisecond * 150)
+	}
+}

13-loops/exercises/01-loops/07-crunch-the-primes/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: Crunch the primes
+//
+//  1. Get numbers from the command-line.
+//  2. `for range` over them.
+//  4. Convert each one to an int.
+//  5. If one of the numbers isn't an int, just skip it.
+//  6. Print the ones that are only the prime numbers.
+//
+// RESTRICTION
+//  The user can run the program with any number of
+//  arguments.
+//
+// HINT
+//  Find whether a number is prime using this algorithm:
+//  https://stackoverflow.com/a/1801446/115363
+//
+// EXPECTED OUTPUT
+//  go run main.go 2 4 6 7 a 9 c 11 x 12 13
+//  2 7 11 13
+// ---------------------------------------------------------
+
+func main() {
+}

13-loops/exercises/01-loops/07-crunch-the-primes/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"
+	"os"
+	"strconv"
+)
+
+//
+func main() {
+	// remember [1:] skips the first argument
+
+main:
+	for _, arg := range os.Args[1:] {
+		n, err := strconv.Atoi(arg)
+		if err != nil {
+			// skip non-numerics
+			continue
+		}
+
+		switch {
+		// not a prime
+		case n <= 0 || n%2 == 0 || n%3 == 0:
+			continue
+
+		// prime
+		case n == 2 || n == 3:
+			fmt.Print(n, " ")
+			continue
+		}
+
+		for i, w := 5, 2; i*i <= n; {
+			// not a prime
+			if n%i == 0 {
+				continue main
+			}
+
+			i += w
+			w = 6 - w
+		}
+
+		// all checks ok: it's a prime
+		fmt.Print(n, " ")
+	}
+
+	fmt.Println()
+}