Questions tagged [pass-by-const-reference]
52 questions
1
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1 answer
(C++) Using multiple operator overloads with const reference parameters
I have been working on a matrix class and I have recently learnt about passing const references to operator overloads so that I can have multiple of them on the same line. The problem I encountered is when defining a function for an operator…
1
vote
1 answer
Why can't we pass const values by reference to inout functions in swift?
In C, although we declare a value as const int a = 5;, we can pass &a to a function declared as void someFun(const int *);.
As a rule of thumb, in C, when the original value is need not to be changed, i) if the size of object is less than or equal…
Sourav Kannantha B
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1
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2 answers
Why does string_view::operator== accepts parameters by value
I was reading source code of string_view, and found that operator== accepts parameters by value.
template
constexpr bool
operator==(basic_string_view<_CharT, _Traits> __x,
…
Jouni
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1
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2 answers
Should templated math functions take values or const references?
Suppose I want to implement some simple mathematical function; for example suppose it's a reimplementation of (C++17's) std::clamp: This function takes a number, a lower bound and an upper bound, and sets the number to one of those bounds if its out…
einpoklum
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constant reference parameter gives warning when passing a temporary
The following code gives me a warning about passing a temporary as a parameter to a function which takes a reference:
struct TempObject
{
typedef TempObject& reference;
const int First, Second;
TempObject(int first, int second) :…
bfair
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1
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1 answer
If a variable is passed as a constant does it get passed by reference?
If I pass a variable as a constant does it automatically get passed by reference?
procedure foo(const x : integer)
I can already pass a variable by reference like this:
procedure foo(var y : integer);
Ideally I'd want something like the code…
J_Strauton
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1
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3 answers
How to modify/update the internal state of an object passed by const reference
Passing an object by const reference means we can't modify any of it's members. But suppose the object contains a vector member. How do we write const methods to read the contents of the vector member assuming that a…
mihai
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0
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2 answers
Weird behavior with std::string reference class member
Given this code:
#include
class Foo {
public:
Foo(const std::string& label) : label_(label) {}
void print() {
std::cout << label_;
}
private:
const std::string& label_;
};
int main()…
morpheus
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Is relying on the const-ness of arguments bind to const& parameters a recipe for thread un-safety?
I was just saw code like this
/* whatever */ foo(std::string const& s) {
// stuff
auto L = s.length();
int i{/* init based on L */};
while (i < L) {
// do other stuff and maybe
++i;
}
}
and I was going to suggest that one can…
Enlico
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0
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3 answers
Multiple functions with the same name but their parameters are either constant or received by value or by reference
The title is a bit lengthy, but it's best explained by an example:
Suppose we have the following functions in C++:
void SomeFunction(int num) { //1
}
void SomeFunction(int& num) { //2
}
void SomeFunction(const int& num) { //3
}
void…
DannyBoy
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0
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0 answers
Are temporaries const? Pass by const reference
#include
using namespace std;
void f(const int& x)
{
}
int g()
{
int x = 0;
return x;
}
int main() {
f(g());
}
If i remove the const from f it doesnt work;
What does this mean, is the temporary returned from g a const???
ionescu radu
- 39
- 3
0
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1 answer
Using find_if with a vector of pointers: How to pass pointer by const reference to lambda?
In the following code I try to compare a vector of pointers via find_if and determine which contains a member a == 5 (in this case both of course, but it shows my case). However it doesn't compile.
#include
class obj
{
public:
…
glades
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0
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1 answer
C++ const reference template function argument type is itself a reference, why?
I have the following function:
template
void f(const T& val) {
using value_type = T;
using sub_type = typename value_type::sub_type;
//etc...
}
However, I am running into the problem that the compiler is telling me that T is…
111111
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0
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1 answer
Can we have a setter member function as const referenced from a const object?
I have a class like this :
class XYZ {
public :
bool var1 = true;
ABC *var2 = nullptr;
public :
XYZ() = default;
void SetVar1(bool flag)
{ var1 = flag; }
void SetVar2(ABC *abc)
{ var2 = abc; }
}
I want to know that if my…
Nashez Zubair
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0
votes
1 answer
When is the address of a const reference function parameter unique?
In my example code below, I'd like to know when two calls to log_cref_address will reliably print the same address.
#include
#include
#include
using namespace std;
void log_cref_address(const int& t) {
cout <<…
Taylor Nichols
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