Integer overflow: Difference between revisions
New post showing additional methods introduced in Java 8, in addition to an existing post which was retained.
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(New post showing additional methods introduced in Java 8, in addition to an existing post which was retained.) |
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===Using Java 8===
<syntaxhighlight lang="java">
public final class IntegerOverflow {
public static void main(String[] args) {
// The following examples show that Java allows integer overflow without warning
// and calculates an incorrect result.
// From version 8, Java introduced methods which throw an ArithmeticException when overflow occurs,
// which prevents the calculation of an incorrect result. It also allows the programmer to replace an "int"
// with a "long" and to replace a "long" with a BigInteger.
// Uncomment the lines below to see the use of the new methods:
// addExact(), subtractExact(), multiplyExact() and negateExact().
System.out.println("Signed 32-bit:");
System.out.println(-(-2_147_483_647 - 1));
// System.out.println(Math.negateExact(-2_147_483_647 - 1));
System.out.println(2_000_000_000 + 2_000_000_000);
// System.out.println(Math.addExact(2_000_000_000, 2_000_000_000));
System.out.println(-2_147_483_647 - 2_147_483_647);
// System.out.println(Math.subtractExact(-2_147_483_647, 2_147_483_647));
System.out.println(46_341 * 46_341);
// System.out.println(Math.multiplyExact(46_341, 46_341));
System.out.println((-2_147_483_647 - 1) / -1);
// System.out.println(Math.negateExact(Math.subtractExact(-2_147_483_647, 1) / 1));
System.out.println();
System.out.println("Signed 64-bit:");
System.out.println(-(-9_223_372_036_854_775_807L - 1));
// System.out.println(Math.negateExact(-9_223_372_036_854_775_807L - 1));
System.out.println(5_000_000_000_000_000_000L + 5_000_000_000_000_000_000L);
// System.out.println(Math.addExact(5_000_000_000_000_000_000L, 5_000_000_000_000_000_000L));
System.out.println(-9_223_372_036_854_775_807L - 9_223_372_036_854_775_807L);
// System.out.println(Math.subtractExact(-9_223_372_036_854_775_807L, 9_223_372_036_854_775_807L));
System.out.println(3_037_000_500L * 3_037_000_500L);
// System.out.println(Math.multiplyExact(3_037_000_500L, 3_037_000_500L));
System.out.println((-9_223_372_036_854_775_807L - 1) / -1);
// System.out.println(Math.negateExact(Math.subtractExact(-9_223_372_036_854_775_807L, 1) / 1));
}
}
</syntaxhighlight>
{{ out }}
<pre>
Signed 32-bit:
-2147483648
-294967296
2
-2147479015
-2147483648
Signed 64-bit:
-9223372036854775808
| |||