/*
Six different functions that accept 5 or 7
and return the other number, without using if/switch.
*/
object FlipNumbers {
// 1. Arithmetic sum trick: 5 + 7 = 12
def flipSum(x: Int): Int =
12 - x
// 2. Product trick: 5 * 7 = 35
def flipProduct(x: Int): Int =
35 / x
// 3. XOR trick: 5 ^ 7 = 2
// x ^ 2 flips 5 ↔ 7
def flipXor(x: Int): Int =
x ^ 2
// 4. Modulo-based trick using divisibility:
// x % 7 == 0 → x is 7
// x % 5 == 0 → x is 5
// Boolean → Int via .compare(false) or .toInt in Scala 3
def flipMod(x: Int): Int =
5 * (if (x % 7 == 0) 1 else 0) +
7 * (if (x % 5 == 0) 1 else 0)
// 5. Absolute-value trick: |x - 12| flips 5 ↔ 7
def flipAbs(x: Int): Int =
math.abs(x - 12)
// 6. Array lookup using arithmetic index:
// For x = 5 → (5 - 5) / 2 = 0 → table(0) = 7
// For x = 7 → (7 - 5) / 2 = 1 → table(1) = 5
def flipArray(x: Int): Int = {
val table = Array(7, 5)
val index = (x - 5) / 2
table(index)
}
def main(args: Array[String]): Unit = {
println(s"flip_sum(5) = ${flipSum(5)}")
println(s"flip_sum(7) = ${flipSum(7)}")
println()
println(s"flip_product(5) = ${flipProduct(5)}")
println(s"flip_product(7) = ${flipProduct(7)}")
println()
println(s"flip_xor(5) = ${flipXor(5)}")
println(s"flip_xor(7) = ${flipXor(7)}")
println()
println(s"flip_mod(5) = ${flipMod(5)}")
println(s"flip_mod(7) = ${flipMod(7)}")
println()
println(s"flip_abs(5) = ${flipAbs(5)}")
println(s"flip_abs(7) = ${flipAbs(7)}")
println()
println(s"flip_array(5) = ${flipArray(5)}")
println(s"flip_array(7) = ${flipArray(7)}")
}
}
/*
OUTPUT:
flip_sum(5) = 7
flip_sum(7) = 5
flip_product(5) = 7
flip_product(7) = 5
flip_xor(5) = 7
flip_xor(7) = 5
flip_mod(5) = 7
flip_mod(7) = 5
flip_abs(5) = 7
flip_abs(7) = 5
flip_array(5) = 7
flip_array(7) = 5
*/
