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
7
votes
2 answers
What happens in Rust programming language when an integer arithmetic operation overflows?
As far as I know, in C programming language(and many C - based languages), when an arithmetic operation overflows over an N-bit integer, this overflow shortens the result to modulo N-th power of 2,
retaining only the LSB's of the resultant.
What…
Hari Krishnan U
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7
votes
4 answers
How can I compute a * b / c when both a and b are smaller than c, but a * b overflows?
Assuming that uint is the largest integral type on my fixed-point platform, I have:
uint func(uint a, uint b, uint c);
Which needs to return a good approximation of a * b / c.
The value of c is greater than both the value of a and the value of…
goodvibration
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7
votes
3 answers
How to Idiomatically Test for Overflow when Shifting Left (<<) in Rust?
For most operators that might overflow, Rust provides a checked version. For example, to test if an addition overflows one could use checked_add:
match 255u8.checked_add(1) {
Some(_) => println!("no overflow"),
None =>…
chuck
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What happens if Date.now () is greater than Number.MAX_SAFE_INTEGER?
Of course it took another 200,000 years for that to happen. But will the Javascript dating system error after the value of Date.now() exceeds the value of Number.MAX_SAFE_INTEGER? What consequences will occur?
Maybe this question looks strange and…
Laode Muhammad Al Fatih
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7
votes
4 answers
List sum too large, throwing overflow exception
I have a list of prime numbers up to 2 000 000. That's a list containing almost 150 000 very large integers. I want a sum of all the numbers in it. Here's a random list of large integers just for demonstration:
List numbers = new…
Milan Vodák
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1 answer
Why doesn't this program overflow?
Trying to study how C# reacts to overflows, I wrote this simple code :
static uint diff(int a, int b)
{
return (uint)(b - a);
}
static void Main(string[] args)
{
Console.Out.WriteLine(int.MaxValue);
uint l = diff(int.MinValue,…
Hey
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7
votes
4 answers
3 * 1000000000 overflows as an int, but the variable is long long. Why?
I have a simple c++ app that performs the following calculations
long long calcOne = 3 * 100000000; // 3e8, essentially
long long calcTwo = 3 * 1000000000; // 3e9, essentially
long long calcThree = 3 * 10000000000; // 3e10, essentially
If I…
John Voss
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7
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2 answers
1000000000 * 3 = -1294967296?
I'm confused!
Today is November 3rd
DateTime DateTime = new DateTime(2010,11,3);
long shazbot = 1000000000 * DateTime.Day;
shazbot comes out to -1294967296
Huh???
sooprise
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7
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Can someone explain overflow in C# using binary?
I'm currently reading a book on C# programming and it has brief intro to Overflow and Underflow and the writer gives a general idea of what happens when you go over the allowed range of a certain type.
Example
short a = 30000;
short b =…
Shabubble
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7
votes
2 answers
Does this function for detecting integer addition overflow actually work?
While reading the comments for this question, I came across a link to the comp.lang.c FAQ that shows a "careful addition function" which purportedly detects integer overflow:
int
chkadd(int a, int b)
{
if (INT_MAX - b < a) {
fputs("int…
zennehoy
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7
votes
1 answer
Chaining checked arithmetic operations in Rust
When doing integer arithmetic with checks for overflows, calculations often need to compose several arithmetic operations. A straightforward way of chaining checked arithmetic in Rust uses checked_* methods and Option chaining:
fn…
mzabaluev
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7
votes
3 answers
Why does integer overflow cause errors with C++ iostreams?
Ok, so I have some problems with C++ iostreams that feels very odd, but it is probably defined behaviour, considering this happens with both MSVC++ and G++.
Say I have this program:
#include
using namespace std;
int main()
{
int a;
…
Maister
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7
votes
3 answers
arithmetic exception in C#
Why in C# is Example A valid, compilable and will just wrap while examples B will not compile?
A
int val = 0;
val = val + Int32.MaxValue +2;
or
int val = Int32.MaxValue;
val++;
B
int val = 0;
val = 2147483647 + 1;
or
int val = 0;
int val =…
Chris G
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7
votes
1 answer
Integer overflow with UDL (user defined literal) for __int128 @ min negative value
For clarity and simplicity I will shorten the following numbers as follows:
−170,141,183,460,469,231,731,687,303,715,884,105,728 as -170…728
170,141,183,460,469,231,731,687,303,715,884,105,727 as 170…727
These numbers represent the minimum and…
bolov
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7
votes
1 answer
Delphi: How do i use $OVERFLOWCHECKS OFF to disable overflow checks?
i have bit of code that causes an underflow:
var
t1, t2, delta: DWORD:
begin
t1 := 0xffffff00;
t2 := 0x00000037;
delta := (t2 - t1);
The subtraction itself does generate an overflow (underflow), but i don't want Delphi to throw an…
Ian Boyd
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