An unsigned variable is a variable that can only represent non-negative numbers.
An unsigned variable is a variable that can only represent non-negative numbers, as opposed to a signed variable which can represent both positive and negative numbers.
Questions tagged [unsigned]
1251 questions
12
votes
5 answers
Unsigned and Signed Extension
Can someone explain the following code output to me:
void myprint(unsigned long a)
{
printf("Input is %lx\n", a);
}
int main()
{
myprint(1 << 31);
myprint(0x80000000);
}
output with gcc main.c :
Input is ffffffff80000000
Input is…
Saksham Jain
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12
votes
4 answers
Is it safe to use negative integers with size_t?
I just saw some C++ code like this. It was using a condition to decide whether to walk forward or backward through a std::vector. The compiler doesn't complain, but I thought size_t was unsigned. Is this dangerous?
vector v { 1,2,3,4,5 }; …
Rob N
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votes
6 answers
What should happen to the negation of a size_t (i.e. `-sizeof(struct foo)`))?
I'm dealing with some code at work that includes an expression of the form
-(sizeof(struct foo))
i.e. the negation of a size_t, and I'm unclear on what the C and C++ standards require of compilers when they see this. Specifically, from looking…
Phil Miller
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12
votes
1 answer
Unsigned minus unsigned difference between 32 and 64-bit
The situation:
I have a piece of code that works when compiled for 32-bits but fails when compiled for 64-bits with gcc 4.6. After identifying the problem and reading up on the standards, I cannot really understand why it is working for 32-bits. I…
Leo
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11
votes
14 answers
C reverse bits in unsigned integer
I'm converting an unsigned integer to binary using bitwise operators, and currently do integer & 1 to check if bit is 1 or 0 and output, then right shift by 1 to divide by 2. However the bits are returned in the wrong order (reverse), so I thought…
user1139103
11
votes
6 answers
Is unsigned char i equivalent to unsigned j?
In following program I used unsigned keyword.
#include
int main()
{
unsigned char i = 'A';
unsigned j = 'B';
printf(" i = %c j = %c", i, j);
}
Output:
i = A j = B
Is unsigned char i equivalent to unsigned j?
msc
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11
votes
2 answers
Data type promotions during arithmetic operations: -1 < (unsinged int) 1 == false
main() {
if ( -1 < (unsigned char) 1 )
printf("less than");
else
printf("NOT less than");
}
Prints less than. Because, (unsigned char) 1 is converted to (signed char) 1 and then: (signed) -1 < (signed) 1, thus output is…
bakra
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11
votes
14 answers
The importance of declaring a variable as unsigned
Is it important to declare a variable as unsigned if you know it should never be negative? Does it help prevent anything other than negative numbers being fed into a function that shouldn't have them?
Rarge
- 155
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11
votes
1 answer
Why would we use addiu instead of addi?
In MIPS assembly, what is the benefit of using addiu over addi? Isn't addiu unsigned (and will ruin our calculations?)
chickenman
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11
votes
3 answers
How to convert signed 32-bit int to unsigned 32-bit int?
This is what I have, currently. Is there any nicer way to do this?
import struct
def int32_to_uint32(i):
return struct.unpack_from("I", struct.pack("i", i))[0]
Claudiu
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10
votes
5 answers
what's the point using unsigned int in C?
I thought that unsigned int could store only integers >= 0.
But I tried assigning a negative to an unsigned int, nothing special happened.
It seems like it stored the value with no problem.
So what is the difference between signed and unsigned int,…
Danny
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10
votes
3 answers
Xcode 10: Where is the don't code sign option in Code Signing Identity
I'm building a Unity iOS app for a client in the form of an unsigned XCArchive as the client signs the XCArchive manually for security reasons.
I was following this guide beforehand: How to build and sign an iOS app on separate machines?
But I…
quaternion
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10
votes
2 answers
scanf %u negative number?
I have tried scanf("%u",&number) and I have entered negative number the problem is when I printf("%d",number) I get the negative number. I thought this will prevent me from reading negative number.
Are scanf("%d",&number) and scanf("%u",&number) the…
rondino
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10
votes
4 answers
*Might* an unsigned char be equal to EOF?
When using fgetc to read the next character of a stream, you usually check that the end-of-file was not attained by
if ((c = fgetc (stream)) != EOF)
where c is of int type. Then, either the end-of-file has been attained and the condition will fail,…
Rémi Peyre
- 410
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10
votes
2 answers
Something wrong with javascript unsigned shift operator on iPad?
I accidentally ran into what appears to be a very strange bug in Safari's javascript engine on iPad.
The unsigned shift operator >>> is supposed to bitwise right-shift a number. I experienced some errors in a script that worked fine on other…
Rogier
- 153
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