Integer overflow occurs when the result of an operation is larger than the maximal value that can be represented by the underlying integer type.
Questions tagged [integer-overflow]
1056 questions
8
votes
10 answers
Java multiply operation behavior
I wrote a method to convert a given number from days to milliseconds:
private long expireTimeInMilliseconds;
...
public void setExpireTimeInDays(int expireTimeInDays)
{
expireTimeInMilliseconds = expireTimeInDays * 24 * 60 * 60 * 1000;
}
I had a…
Gilberto Olimpio
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8
votes
1 answer
How do reference-counting smart pointer's avoid or handle reference-counter overflows?
In a naive reference-counting smart pointer implementation, the reference-counter could overflow. How is this overflow avoided or handled in C++ standard library implementations?
sergej
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8
votes
1 answer
Go print large number
I am currently doing the Go Lang tutorial, "Numeric Constants" to be precise. The example code starts with the following statement:
const (
// Create a huge number by shifting a 1 bit left 100 places.
// In other words, the binary number…
arik
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8
votes
1 answer
c# uint to ushort overflow like in native C
I have the following piece of example code:
UInt16 a = 0x3A;
UInt16 b = 0xFFDF;
UInt16 result = Convert.ToUInt16(a - b);
line 3 errors with an Overflow exception. However i want to achieve the same result like i would subtract 2 unsigned shorts in…
eKKiM
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8
votes
1 answer
Why does this multiplication integer overflow result in zero?
After answering this question, I was confused about why the overflowing integer in this code resulted in 0 instead of a negative number. It's strange, why such an exact number? Why 0?
public class IntegerOverflow {
public static void main(String[]…
durron597
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8
votes
6 answers
Force PHP integer overflow
We have some integer arithmetic which for historical reasons has to work the same on PHP as it does in a few statically typed languages. Since we last upgraded PHP the behavior for overflowing integers has changed. Basically we are using following…
Kris Erickson
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8
votes
1 answer
Do numerical programming languages distinguish between a "largest finite number" and "infinity"?
Question motivation:
In standard numerical languages of which I am aware (e.g. Matlab, Python numpy, etc.), if, for example, you take the exponential of a modestly large number, the output is infinity as the result of numerical overflow. If this is…
Josh
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- 5
8
votes
1 answer
Metafunction to compute x^n and return the integer limit without overflow if not possible?
Consider the following code:
template
struct integer_power_bounded
{
static_assert(Exponent >= 0,
"Error in 'integer_power_bounded': 'Exponent >= 0' is false");
static…
Vincent
- 57,703
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8
votes
1 answer
R: simple multiplication causes integer overflow
In a longer script I have to multiply the length of a vector A (2614) with the numbers of rows of a dataframe B (1456000). If I do that directly with length(A) * nrow(B) I get the message NAs produced by integer overflow although there's no problem…
user7417
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8
votes
2 answers
Integer overflow not consistent
Pardon me if this question has been posed before. I looked for answers to similar questions, but I'm still puzzled with my problem. So I will shoot the question anyway.
I'm using a C library called libexif for image data. I run my application (which…
Spottsworth
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8
votes
2 answers
Integer overflow using lazy sequences in Clojure
I'm just learning to use lazy sequences in Clojure, and I'm not sure what I'm doing wrong in the following code:
(defn sum [seqn]
(reduce + seqn))
(defn fib
([] (concat [0 1] (fib 0 1)))
([a b] (lazy-seq (cons (+ a b) (fib b (+ a…
Chetan
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7
votes
5 answers
Permutation with Repetition: Avoiding Overflow
Background:
Given n balls such that:
'a' balls are of colour GREEN
'b' balls are of colour BLUE
'c' balls are of colour RED
...
(of course a + b + c + ... = n)
The number of permutations in which these balls can be arranged is given by:
perm = n! /…
ArjunShankar
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7
votes
2 answers
Why do my .net Int64's behaves as if they were Int32's?
I'm witnessing a strange behavior in a .net program :
Console.WriteLine(Int64.MaxValue.ToString());
// displays 9223372036854775807, which is 2^63-1, as expected
Int64 a = 256*256*256*127; // ok
Int64 a = 256*256*256*128; // compile time error :…
Brann
- 31,689
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7
votes
4 answers
C integer overflow behaviour when assigning to larger-width integers
If I execute the following code in C:
#include
uint16_t a = 4000;
uint16_t b = 8000;
int32_t c = a - b;
printf("%d", c);
It correctly prints '-4000' as the result. However, I'm a little confused: shouldn't there be an arithmetic…
Davorian
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7
votes
2 answers
Why does Rust perform integer overflow checks in --release?
I have this piece of simple code:
let val: u8 = 255 + 1;
println!("{}", val);
It is said here that such a code will compile normally if run with the --release flag.
I am running this code via cargo run --release, and I still see the checks:
error:…
Oleksandr Novik
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