using System;
class FlipNumbers
{
/*
Six different functions that accept 5 or 7
and return the other number, without using if/switch.
*/
// 1. Arithmetic sum trick: 5 + 7 = 12
static int FlipSum(int x) {
return 12 - x;
}
// 2. Product trick: 5 * 7 = 35
static int FlipProduct(int x) {
return 35 / x;
}
// 3. XOR trick: 5 ^ 7 = 2
// x ^ 2 flips 5 ↔ 7
static int FlipXor(int x) {
return x ^ 2;
}
// 4. Modulo-based trick using divisibility:
// x % 7 == 0 → x is 7
// x % 5 == 0 → x is 5
// Boolean → int via Convert.ToInt32()
static int FlipMod(int x) {
return 5 * Convert.ToInt32(x % 7 == 0)
+ 7 * Convert.ToInt32(x % 5 == 0);
}
// 5. Absolute-value trick: |x - 12| flips 5 ↔ 7
static int FlipAbs(int x) {
return 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
static int FlipArray(int x) {
int[] table = { 7, 5 };
int index = (x - 5) / 2;
return table[index];
}
static void Main()
{
Console.WriteLine("flip_sum(5) = " + FlipSum(5));
Console.WriteLine("flip_sum(7) = " + FlipSum(7));
Console.WriteLine();
Console.WriteLine("flip_product(5) = " + FlipProduct(5));
Console.WriteLine("flip_product(7) = " + FlipProduct(7));
Console.WriteLine();
Console.WriteLine("flip_xor(5) = " + FlipXor(5));
Console.WriteLine("flip_xor(7) = " + FlipXor(7));
Console.WriteLine();
Console.WriteLine("flip_mod(5) = " + FlipMod(5));
Console.WriteLine("flip_mod(7) = " + FlipMod(7));
Console.WriteLine();
Console.WriteLine("flip_abs(5) = " + FlipAbs(5));
Console.WriteLine("flip_abs(7) = " + FlipAbs(7));
Console.WriteLine();
Console.WriteLine("flip_array(5) = " + FlipArray(5));
Console.WriteLine("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
*/
