update: foundations

x-tba/foundations/03-if-switch-loop/01-for-crunch-the-primes/main.go

@@ -16,10 +16,18 @@ import (
 )
 
 func main() {
+	const usageMsg = `Type a couple of unique numbers.
+Separate them with spaces.`
+
 	// remember [1:] skips the first argument
+	args := os.Args[1:]
+	if len(args) == 0 {
+		fmt.Println(usageMsg)
+		return
+	}
 
 main:
-	for _, arg := range os.Args[1:] {
+	for _, arg := range args {
 		n, err := strconv.Atoi(arg)
 		if err != nil {
 			// skip non-numerics

x-tba/foundations/03-if-switch-loop/03-math-table-if-switch-loop/main.go

@@ -15,31 +15,21 @@ import (
 )
 
 const (
-	validOps = "%*/+-"
-
-	usageMsg       = "Usage: [op=" + validOps + "] [size]"
-	sizeMissingMsg = "Size is missing"
+	validOps       = "* / + - mul div add sub"
+	usageMsg       = "Usage: [valid ops: " + validOps + "] [size]"
+	sizeMissingMsg = "Size is missing\n" + usageMsg
 	invalidOpMsg   = `Invalid operator.
 Valid ops one of: ` + validOps
-
-	invalidOp = -1
 )
 
 func main() {
+	// CHECK THE ARGUMENTS
 	args := os.Args[1:]
-
-	switch l := len(args); {
-	case l == 1:
+	if l := len(args); l == 1 {
 		fmt.Println(sizeMissingMsg)
-		fallthrough
-	case l < 1:
-		fmt.Println(usageMsg)
 		return
-	}
-
-	op := args[0]
-	if strings.IndexAny(op, validOps) == invalidOp {
-		fmt.Println(invalidOpMsg)
+	} else if l < 1 {
+		fmt.Println(usageMsg)
 		return
 	}
 
@@ -49,12 +39,32 @@ func main() {
 		return
 	}
 
+	// CHECK THE VALIDITY OF THE OP
+	op, ops := args[0], strings.Fields(validOps)
+
+	var ok bool
+	for _, o := range ops {
+		if strings.ToLower(o) == op {
+			ok = true
+			break
+		}
+	}
+
+	if !ok {
+		fmt.Println(invalidOpMsg)
+		return
+	}
+
+	// PRINT THE TABLE
+
+	// HEADER
 	fmt.Printf("%5s", op)
 	for i := 0; i <= size; i++ {
 		fmt.Printf("%5d", i)
 	}
 	fmt.Println()
 
+	// CELLS
 	for i := 0; i <= size; i++ {
 		fmt.Printf("%5d", i)
 
@@ -62,22 +72,24 @@ func main() {
 			var res int
 
 			switch op {
-			case "*":
+			default:
+				fallthrough // default is multiplication
+			case "*", "mul":
 				res = i * j
-			case "%":
-				if j != 0 {
-					res = i % j
-				}
-			case "/":
-				if j != 0 {
-					res = i / j
-				}
-			case "+":
+			case "+", "add":
 				res = i + j
-			case "-":
+			case "-", "sub":
 				res = i - j
+			case "%", "mod":
+				if j == 0 {
+					// continue // will continue the loop
+					break // breaks the switch
+				}
+				res = i % j
 			}
 
+			// break // breaks the loop
+
 			fmt.Printf("%5d", res)
 		}
 		fmt.Println()

x-tba/foundations/03-if-switch-loop/04-lucky-number-if-for-switch/main.go

@@ -44,7 +44,7 @@ func main() {
 		verbose = true
 	}
 
-	guess, err := strconv.Atoi(args[0])
+	guess, err := strconv.Atoi(args[len(args)-1])
 	if err != nil {
 		fmt.Println("Not a number.")
 		return
@@ -75,13 +75,36 @@ func main() {
 		}
 	}
 
-	msg := "%s Try again?\n"
+	// msg, n := "%s Try again?\n", rand.Intn(5)
+	// if msg, n := "%s Try again?\n", rand.Intn(5); n <= 2 {
+	// 	fmt.Printf(msg, "☠️  YOU LOST...")
+	// } else if n < 3 {
+	// 	fmt.Printf(msg, "☠️  JUST A BAD LUCK...")
+	// } else if n == 4 {
+	// 	fmt.Printf(msg, "☠️  TRY NEXT TIME...")
+	// }
 
-	switch rand.Intn(2) {
-	case 0:
-		fmt.Printf(msg, "☠️  YOU LOST...")
-	case 1:
-		fmt.Printf(msg, "☠️  JUST A BAD LUCK...")
+	// var msg string
+	// switch rand.Intn(10) {
+	// // more probability
+	// case 0, 1, 2, 3, 4, 5:
+	// 	msg = "☠️  YOU LOST..."
+	// case 6, 7, 8:
+	// 	msg = "☠️  JUST A BAD LUCK..."
+	// default:
+	// 	msg = "☠️  TRY NEXT TIME..."
+	// }
+	// fmt.Printf("%s Try again?\n", msg)
+
+	var msg string
+	switch n := rand.Intn(10); {
+	// more probability
+	case n <= 5:
+		msg = "☠️  YOU LOST..."
+	case n <= 8:
+		msg = "☠️  JUST A BAD LUCK..."
+	default:
+		msg = "☠️  TRY NEXT TIME..."
 	}
-
+	fmt.Printf("%s Try again?\n", msg)
 }

x-tba/foundations/03-if-switch-loop/05-path-searcher-for-range/main.go

@@ -32,9 +32,11 @@ func main() {
 		for i, w := range words {
 			q, w = strings.ToLower(q), strings.ToLower(w)
 
-			if strings.Contains(w, q) {
-				fmt.Printf("#%-2d: %q\n", i+1, w)
+			if !strings.Contains(w, q) {
+				continue
 			}
+
+			fmt.Printf("#%-2d: %q\n", i+1, w)
 		}
 	}
 }