Data commit

Task/Test-integerness/Kotlin/test-integerness.kotlin

@@ -0,0 +1,68 @@
+// version 1.1.2
+
+import java.math.BigInteger
+import java.math.BigDecimal
+
+fun Double.isLong(tolerance: Double = 0.0) =
+    (this - Math.floor(this)) <= tolerance || (Math.ceil(this) - this) <= tolerance
+
+fun BigDecimal.isBigInteger() =
+    try {
+        this.toBigIntegerExact()
+        true
+    }
+    catch (ex: ArithmeticException) {
+        false
+    }
+
+class Rational(val num: Long, val denom: Long) {
+    fun isLong() = num % denom == 0L
+
+    override fun toString() = "$num/$denom"
+}
+
+class Complex(val real: Double, val imag: Double) {
+    fun isLong() = real.isLong() && imag == 0.0
+
+    override fun toString() =
+        if (imag >= 0.0)
+            "$real + ${imag}i"
+        else
+            "$real - ${-imag}i"
+}
+
+fun main(args: Array<String>) {
+    val da = doubleArrayOf(25.000000, 24.999999, 25.000100)
+    for (d in da) {
+        val exact = d.isLong()
+        println("${"%.6f".format(d)} is ${if (exact) "an" else "not an"} integer")
+    }
+    val tolerance = 0.00001
+    println("\nWith a tolerance of ${"%.5f".format(tolerance)}:")
+    for (d in da) {
+        val fuzzy = d.isLong(tolerance)
+        println("${"%.6f".format(d)} is ${if (fuzzy) "an" else "not an"} integer")
+    }
+
+    println()
+    val fa = doubleArrayOf(-2.1e120, -5e-2, Double.NaN, Double.POSITIVE_INFINITY)
+    for (f in fa) {
+        val exact = if (f.isNaN() || f.isInfinite()) false
+                    else BigDecimal(f.toString()).isBigInteger()
+        println("$f is ${if (exact) "an" else "not an"} integer")
+    }
+
+    println()
+    val ca = arrayOf(Complex(5.0, 0.0), Complex(5.0, -5.0))
+    for (c in ca) {
+        val exact = c.isLong()
+        println("$c is ${if (exact) "an" else "not an"} integer")
+    }
+
+    println()
+    val ra = arrayOf(Rational(24, 8), Rational(-5, 1), Rational(17, 2))
+    for (r in ra) {
+        val exact = r.isLong()
+        println("$r is ${if (exact) "an" else "not an"} integer")
+    }
+}