RosettaCodeData/Task/Loops-Wrong-ranges/C-sharp/loops-wrong-ranges-1.cs
2023-07-01 13:44:08 -04:00

49 lines
1.7 KiB
C#

using System;
using System.Collections.Generic;
static class Program
{
static void Main()
{
Example(-2, 2, 1, "Normal");
Example(-2, 2, 0, "Zero increment");
Example(-2, 2, -1, "Increments away from stop value");
Example(-2, 2, 10, "First increment is beyond stop value");
Example(2, -2, 1, "Start more than stop: positive increment");
Example(2, 2, 1, "Start equal stop: positive increment");
Example(2, 2, -1, "Start equal stop: negative increment");
Example(2, 2, 0, "Start equal stop: zero increment");
Example(0, 0, 0, "Start equal stop equal zero: zero increment");
}
static IEnumerable<int> Range(int start, int stop, int increment)
{
// To replicate the (arguably more correct) behavior of VB.NET:
//for (int i = start; increment >= 0 ? i <= stop : stop <= i; i += increment)
// Decompiling the IL emitted by the VB compiler (uses shifting right by 31 as the signum function and bitwise xor in place of the conditional expression):
//for (int i = start; ((increment >> 31) ^ i) <= ((increment >> 31) ^ stop); i += increment)
// "Naïve" translation.
for (int i = start; i <= stop; i += increment)
yield return i;
}
static void Example(int start, int stop, int increment, string comment)
{
// Add a space, pad to length 50 with hyphens, and add another space.
Console.Write((comment + " ").PadRight(50, '-') + " ");
const int MAX_ITER = 9;
int iteration = 0;
foreach (int i in Range(start, stop, increment))
{
Console.Write("{0,2} ", i);
if (++iteration > MAX_ITER) break;
}
Console.WriteLine();
}
}