Test integerness: Difference between revisions
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'''Example''':<lang j> isInt 3.14 7 1.4j0 4j0 5j3
0 1 0 1 0</lang>
=={{header|Java}}==
{{trans|Kotlin}}
<lang Java>import java.math.BigDecimal;
import java.util.List;
public class TestIntegerness {
private static boolean isLong(double d) {
return isLong(d, 0.0);
}
private static boolean isLong(double d, double tolerance) {
return (d - Math.floor(d)) <= tolerance || (Math.ceil(d) - d) <= tolerance;
}
@SuppressWarnings("ResultOfMethodCallIgnored")
private static boolean isBigInteger(BigDecimal bd) {
try {
bd.toBigIntegerExact();
return true;
} catch (ArithmeticException ex) {
return false;
}
}
private static class Rational {
long num;
long denom;
Rational(int num, int denom) {
this.num = num;
this.denom = denom;
}
boolean isLong() {
return num % denom == 0;
}
@Override
public String toString() {
return String.format("%s/%s", num, denom);
}
}
private static class Complex {
double real;
double imag;
Complex(double real, double imag) {
this.real = real;
this.imag = imag;
}
boolean isLong() {
return TestIntegerness.isLong(real) && imag == 0.0;
}
@Override
public String toString() {
if (imag >= 0.0) {
return String.format("%s + %si", real, imag);
}
return String.format("%s - %si", real, imag);
}
}
public static void main(String[] args) {
List<Double> da = List.of(25.000000, 24.999999, 25.000100);
for (Double d : da) {
boolean exact = isLong(d);
System.out.printf("%.6f is %s integer%n", d, exact ? "an" : "not an");
}
System.out.println();
double tolerance = 0.00001;
System.out.printf("With a tolerance of %.5f:%n", tolerance);
for (Double d : da) {
boolean fuzzy = isLong(d, tolerance);
System.out.printf("%.6f is %s integer%n", d, fuzzy ? "an" : "not an");
}
System.out.println();
List<Double> fa = List.of(-2.1e120, -5e-2, Double.NaN, Double.POSITIVE_INFINITY);
for (Double f : fa) {
boolean exact = !f.isNaN() && !f.isInfinite() && isBigInteger(new BigDecimal(f.toString()));
System.out.printf("%s is %s integer%n", f, exact ? "an" : "not an");
}
System.out.println();
List<Complex> ca = List.of(new Complex(5.0, 0.0), new Complex(5.0, -5.0));
for (Complex c : ca) {
boolean exact = c.isLong();
System.out.printf("%s is %s integer%n", c, exact ? "an" : "not an");
}
System.out.println();
List<Rational> ra = List.of(new Rational(24, 8), new Rational(-5, 1), new Rational(17, 2));
for (Rational r : ra) {
boolean exact = r.isLong();
System.out.printf("%s is %s integer%n", r, exact ? "an" : "not an");
}
}
}</lang>
{{out}}
<pre>25.000000 is an integer
24.999999 is not an integer
25.000100 is not an integer
With a tolerance of 0.00001:
25.000000 is an integer
24.999999 is an integer
25.000100 is not an integer
-2.1E120 is an integer
-0.05 is not an integer
NaN is not an integer
Infinity is not an integer
5.0 + 0.0i is an integer
5.0 - -5.0i is not an integer
24/8 is an integer
-5/1 is an integer
17/2 is not an integer</pre>
=={{header|jq}}==
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