Merge pull request #7 from tainguyenbp/feat/learning-hacking-with-gol…

…ang03

learn hacking with golang

hacking-go/learn04/if/ifelse.go

@@ -3,11 +3,14 @@ package main
 import "fmt"
 
 func main() {
-	if var1 := 10; var1 > 20 {
+	if var1 := 5; var1 > 20 {
 		fmt.Println("Value inside if:", var1)
 	} else {
-		// Can use var1 here
-		fmt.Println("Value inside else:", var1)
+		if var1 > 5 {
+			fmt.Println("Value inside nested if:", var1) // This block executes if var1 <= 20 and var1 > 5
+		} else {
+			fmt.Println("Value inside nested else:", var1) // This block executes if var1 <= 5
+		}
 	}
 
 }

hacking-go/learn04/if/ifelse1.go

@@ -0,0 +1,17 @@
+package main
+
+import "fmt"
+
+func main() {
+	var1 := 3
+	if var1 > 20 {
+		fmt.Println("Value inside if:", var1)
+	} else {
+		if var1 > 5 {
+			fmt.Println("Value inside nested if:", var1) // This block executes if var1 <= 20 and var1 > 5
+		} else {
+			fmt.Println("Value inside nested else:", var1) // This block executes if var1 <= 5
+		}
+	}
+
+}

hacking-go/learn04/if/ifelse2.go

@@ -0,0 +1,21 @@
+package main
+
+import "fmt"
+
+func main() {
+	var var1 int = 10 // Declare and initialize var1
+
+	if var1 > 20 {
+		fmt.Println("var1 is greater than 20")
+	} else {
+		if var1 > 15 {
+			fmt.Println("var1 is greater than 15 but less than or equal to 20")
+		} else {
+			if var1 > 10 {
+				fmt.Println("var1 is greater than 10 but less than or equal to 15")
+			} else {
+				fmt.Println("var1 is 10 or less")
+			}
+		}
+	}
+}

hacking-go/learn04/if/ifelse3.go

@@ -0,0 +1,18 @@
+package main
+
+import "fmt"
+
+func main() {
+	var var1 int = 10
+	var var2 int = 25
+
+	if var1 > 20 && var2 > 30 {
+		fmt.Println("var1 is greater than 20 and var2 is greater than 30")
+	} else if var1 > 15 || var2 > 20 {
+		fmt.Println("Either var1 is greater than 15 or var2 is greater than 20")
+	} else if var1 == 10 {
+		fmt.Println("var1 is exactly 10")
+	} else {
+		fmt.Println("None of the conditions were met")
+	}
+}

hacking-go/learn04/switch/switch.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"math/rand" // This is not cryptographically secure!
+	"time"
+)
+
+func main() {
+	// Seeding rand
+	rand.Seed(time.Now().UnixNano())
+	fmt.Println("Choosing a random number:")
+	switch num := rand.Intn(3); num {
+	case 1:
+		fmt.Println("1")
+	case 2:
+		fmt.Println("2")
+	default:
+		fmt.Println("3")
+	}
+}

hacking-go/learn04/switch/switch1.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+func main() {
+	// Seeding rand with the current time in nanoseconds to get different results each time
+	rand.Seed(time.Now().UnixNano())
+	fmt.Println("Choosing a random number:")
+
+	// Generating a random number between 0 and 2 (inclusive)
+	switch num := rand.Intn(3); num {
+	case 1:
+		fmt.Println("1")
+	case 2:
+		fmt.Println("2")
+	default:
+		fmt.Println("3") // This will handle the case when num is 0
+	}
+}

hacking-go/learn04/switch/switch2.go

@@ -0,0 +1,27 @@
+package main
+
+import "fmt"
+
+func main() {
+	var num int
+	fmt.Println("Please enter a number:")
+
+	// Reading input from the user
+	_, err := fmt.Scanln(&num)
+	if err != nil {
+		fmt.Println("Please enter number type int, error reading input:", err)
+		return
+	}
+
+	fmt.Println("You entered:", num)
+
+	// Using switch statement to handle different cases
+	switch num {
+	case 1:
+		fmt.Println("You entered one.")
+	case 2:
+		fmt.Println("You entered two.")
+	default:
+		fmt.Println("You entered a number other than one or two.")
+	}
+}

hacking-go/learn04/switch/switch3.go

@@ -0,0 +1,18 @@
+package main
+
+import "fmt"
+
+func main() {
+	var var1 int = 10 // Declare and initialize var1
+
+	switch {
+	case var1 > 20:
+		fmt.Println("var1 is greater than 20")
+	case var1 > 15:
+		fmt.Println("var1 is greater than 15 but less than or equal to 20")
+	case var1 > 10:
+		fmt.Println("var1 is greater than 10 but less than or equal to 15")
+	default:
+		fmt.Println("var1 is 10 or less")
+	}
+}

hacking-go/learn04/switch/switch4.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	var num int
+	fmt.Println("Please enter a number:")
+
+	// Reading input from the user
+	_, err := fmt.Scanln(&num)
+	if err != nil {
+		fmt.Println("Please enter number type int,  error reading input:", err)
+		return
+	}
+
+	fmt.Println("You entered:", num)
+
+	// Using a switch statement to handle different cases
+	switch {
+	case num < 0:
+		fmt.Println("You entered a negative number.")
+	case num == 0:
+		fmt.Println("You entered zero.")
+	case num > 0 && num <= 10:
+		fmt.Println("You entered a positive number between 1 and 10.")
+	case num > 10 && num <= 20:
+		fmt.Println("You entered a positive number between 11 and 20.")
+		fallthrough
+	case num > 20 && num <= 30:
+		fmt.Println("You entered a positive number between 21 and 30.")
+		fallthrough
+	case num > 30:
+		fmt.Println("You entered a number greater than 30.")
+	default:
+		fmt.Println("This case should never be reached.")
+	}
+
+	// Example of handling multiple specific cases
+	switch num {
+	case 1, 2, 3:
+		fmt.Println("You entered a small number (1, 2, or 3).")
+	case 10, 20, 30:
+		fmt.Println("You entered a round number (10, 20, or 30).")
+	default:
+		fmt.Println("You entered a number that is neither small nor round.")
+	}
+}

hacking-go/learn04/switch/switch5.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	var num int
+	fmt.Println("Please enter a number:")
+
+	// Reading input from the user
+	_, err := fmt.Scanln(&num)
+	if err != nil {
+		fmt.Println("Error reading input:", err)
+		return
+	}
+
+	fmt.Println("You entered:", num)
+
+	// Using a switch statement to handle different cases
+	switch {
+	case num < 0:
+		fmt.Println("You entered a negative number.")
+	case num == 0:
+		fmt.Println("You entered zero.")
+	case num > 0 && num <= 10:
+		if num == 5 {
+			fmt.Println("You entered exactly five.")
+		} else {
+			fmt.Println("You entered a positive number between 1 and 10.")
+		}
+	case num > 10 && num <= 20:
+		if num%2 == 0 {
+			fmt.Println("You entered an even number between 11 and 20.")
+		} else {
+			fmt.Println("You entered an odd number between 11 and 20.")
+		}
+		fallthrough
+	case num > 20 && num <= 30:
+		if num%5 == 0 {
+			fmt.Println("You entered a multiple of 5 between 21 and 30.")
+		} else {
+			fmt.Println("You entered a number between 21 and 30.")
+		}
+		fallthrough
+	case num > 30:
+		if num > 50 {
+			fmt.Println("You entered a number greater than 50.")
+		} else {
+			fmt.Println("You entered a number between 31 and 50.")
+		}
+	default:
+		fmt.Println("This case should never be reached.")
+	}
+
+	// Example of handling multiple specific cases with nested if-else
+	switch num {
+	case 1, 2, 3:
+		fmt.Println("You entered a small number (1, 2, or 3).")
+		if num == 2 {
+			fmt.Println("Two is the only even small number.")
+		}
+	case 10, 20, 30:
+		fmt.Println("You entered a round number (10, 20, or 30).")
+		if num == 20 {
+			fmt.Println("Twenty is a nice round number.")
+		}
+	default:
+		fmt.Println("You entered a number that is neither small nor round.")
+	}
+}

hacking-go/learn04/switch/switch6-advan.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"math/rand" // This is not cryptographically secure!
+	"time"
+)
+
+func main() {
+	// Seeding rand
+	rand.Seed(time.Now().UnixNano())
+	fmt.Println("Choosing a random number:")
+	num := rand.Intn(100) // Generate a random number between 0 and 99
+	fmt.Printf("Random number is: %d\n", num)
+
+	// Using switch with advanced conditions and nested if-else
+	switch {
+	case num < 20:
+		fmt.Println("Less than 20")
+		if num < 10 {
+			fmt.Println("Less than 10")
+		} else {
+			fmt.Println("Between 10 and 19")
+		}
+	case num >= 20 && num < 50:
+		fmt.Println("Between 20 and 49")
+		if num%2 == 0 {
+			fmt.Println("Even number")
+		} else {
+			fmt.Println("Odd number")
+		}
+	case num >= 50 && num < 80:
+		fmt.Println("Between 50 and 79")
+		if num%5 == 0 {
+			fmt.Println("Multiple of 5")
+		} else {
+			fmt.Println("Not a multiple of 5")
+		}
+	default:
+		fmt.Println("80 or more")
+		if num > 90 {
+			fmt.Println("Greater than 90")
+		} else {
+			fmt.Println("Between 80 and 89")
+		}
+	}
+
+	// Example of handling multiple specific cases with nested if-else
+	switch num {
+	case 1, 2, 3:
+		fmt.Println("You entered a small number (1, 2, or 3).")
+		if num == 2 {
+			fmt.Println("Two is the only even small number.")
+		}
+	case 10, 20, 30:
+		fmt.Println("You entered a round number (10, 20, or 30).")
+		if num == 20 {
+			fmt.Println("Twenty is a nice round number.")
+		}
+	default:
+		fmt.Println("You entered a number that is neither small nor round.")
+	}
+}

hacking-go/learn04/switch/switch6.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"fmt"
+	"math/rand" // This is not cryptographically secure!
+	"time"
+)
+
+func main() {
+	// Seeding rand
+	rand.Seed(time.Now().UnixNano())
+	fmt.Println("Choosing a random number:")
+	switch num := rand.Intn(100); {
+	case num < 50:
+		fmt.Println("Less than 50")
+	default:
+		fmt.Println("More than 50")
+	}
+}