Questions tagged [const-pointer]
36 questions
10
votes
1 answer
C++ const double pointer
I want to make a constant double pointer points to a constant pointer points to a constant double. I started to make it (of course I make a little search at books and I googled it) from scratch and think what the following three make:
const double*…
chaviaras michalis
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10
votes
5 answers
the type of this* in C++
it might sound stupid.in C++prime 5th edition P258,it says:
by default, the type of this is a const pointer to the nonconst version of the class type.for example,by default, the type of this in a Sales_data member function is Sales_data *const.
i…
ItsJingran
- 147
- 9
8
votes
4 answers
How to find by a const pointer key in a map with non-const pointer keys
The following C++ code does not compile because it's passing a non-const pointer to a find() function which expects a const pointer.
#include
bedrorom
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6
votes
2 answers
Meaning of const pointers as function parameters
I have this function signature:
void myFunction(int *const ptr);
What's the point of the const keyword in this particular context?
Even if ptr wasn't a const variable, I couldn't modify to what address it points to, because it's passed by value, so…
mariusmmg2
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5
votes
3 answers
Why Can't Make a Reference To Pointer for Constant Assign a String Literal
I can make pointer point to string literal, it will cast string literal to constant pointer, but reference to pointer can't assign string literal, for example:
const char *&text = "Hello, World\n";
There's an error, the compiler says I can't cast…
user13739935
5
votes
1 answer
Is it a good idea to use a const pointer to FILE type?
Normally, C file I/O is done using FILE* as this is what the standard library functions all take.
In C, one can also have a const pointer, where the address of the pointer cannot change (but the value it points to can be).
I wondered if this could…
saxbophone
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4
votes
3 answers
Dynamically allocating memory for const char string using malloc()
I am writing a program that reads a value from an .ini file, then passes the value into a function that accepts a PCSTR (i.e. const char *). The function is getaddrinfo().
So, I want to write PCSTR ReadFromIni(). To return a constant string, I plan…
paperduck
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4
votes
2 answers
Iterating through C-style array not using a pointer
I am learning pointer arithmetic and have a piece of code giving me error for quite some time. any help would be appreciated.(I couldnt find it on SO)
int arr [] = {1, 2, 3, 4, 5} ;
for (int i = 0 ; i < 5 ; i++)
{
cout << *arr ;
arr++…
Sasha
- 492
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3
votes
3 answers
Modifying a const pointer in C
I am trying to understand why the following code compiles and runs fine. I would expect any assignment using data inside f not to compile with a gcc error assignment of member ‘i’ in read-only object. Is there some kind of exception, because data.i…
b1000
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3
votes
2 answers
Prefer Iterators Over Pointers?
This question is a bump of a question that had a comment here but was deleted as part of the bump.
For those of you who can't see deleted posts, the comment was on my use of const char*s instead of string::const_iterators in this answer: "Iterators…
Jonathan Mee
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2
votes
1 answer
function returning const pointer
#include
class Test
{
public:
int* i = nullptr;
int* const X()
{
return i;
}
};
int main()
{
Test c;
int x = 2;
c.i = c.X();
c.i = &x;
*c.i += 2;
}
what does the const change in the…
user20295136
2
votes
1 answer
casting int * const to long int * const warning
This may well have been asked in some other way before (I would be surprised if its not) but I am struggling to find it if it is.
Given:
#include
#include
int main()
{
int * const pi = new int(1);
long int * const pl =…
code_fodder
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2
votes
2 answers
How to initialize int *const *const?
I need a 2d array with fixed width and height that can only change the individual values stored in it. It is declared in a header and later initialized in a source file.
What I found made me try the following snippets; unfortunately questions were…
Al.G.
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2
votes
2 answers
c - what does this 2 const mean?
code:
const char * const key;
There are 2 const in above pointer, I saw things like this the first time.
I know the first const makes the value pointed by the pointer immutable,
but did the second const make the pointer itself immutable?
Anyone can…
Eric
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2
votes
1 answer
How to get CConstPointer in Swift?
I want to transform a CGPath with the transform CGAffineTransformMakeRotation(radians) but the CGPathCreateCopyByTransformingPath func takes a CConstPointer. How do I get a CConstPointer out of my…
JuJoDi
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