This question already has answers here:
Use of Curly Brackets (Braces) Around a variable C++
(4 answers)
Initialization difference with or without curly braces in C++
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What are the advantages of list initialization (using curly braces)?
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When should we use parenthesis ( ) vs. initializer { } syntax to initialize objects in C++11? [duplicate]
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When to use the brace-enclosed initializer?
(3 answers)
Closed 3 months ago.
int fr[10]{}
I seen this declaration in C++ is this 1-D array or it is 2-D. Which type of declaration it is?
C++ since its version 11 has introduced in its standard the use of curly brackets for the initialization of objects.
Here are some examples:
MyObjects obj {};
MyObjects obj {firstParameter};
int array[10] {};
In the latter case, it refers to the fact that it will contain 10 elements initialized as zero in it. In the case of the standard types you will see what was written in the memory cell first
Here you will find a precise explanation of all this
Related
This question already has answers here:
Does C++ zero-initialise unspecified values during aggregate initialization?
(2 answers)
Why would my array would be filled out to zero, when I initialised it to -1
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how does array[100] = {0} set the entire array to 0?
(4 answers)
Closed 6 months ago.
I have a constructor that looks like
A (const int(&inArr)[4])
{
...
}
And I can construct an instance with list-initialization as such,
A a({3,4,5,6});
However, I can also construct an instance with a shorter list, e.g. {3,2}, or an empty list {}. From my testing in MSVC and Clang, the array received by the constructor is always zeroed after the values in the list. i.e. {3,2} will be read as [3,2,0,0], and {} as [0,0,0,0].
I am wondering if this is standard behaviour that can be relied upon, or if this may vary across platforms/compilers?
This question already has answers here:
what will happen when std::move with c style array or not movable object
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Can std::move move a built-in types or c pointer or array
(1 answer)
What is std::move(), and when should it be used?
(9 answers)
Closed 8 months ago.
I want to do something like this:
int data[4] = {1,2,3,4};
int otherData[4];
otherData = std::move(data);
compiler says invalid array assignment, so how can I transfer values from data to otherData
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class std::vector has no member named [closed]
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How to print vector's data
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No operator "=" matches these operands
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Closed 5 years ago.
when using the fill method or clear the following error appears
request for member ‘clear’ in ‘adj’, which is of non-class type ‘std::vector [1000005]
the declaration is as follows:
vector<int> adj[1000005];
It's not a vector but an array of 1000005 vectors. To properly define a global vector you'll need to use parentheses (or braces):
vector<int> adj(1000005);
This question already has answers here:
Direct Initialization vs Copy Initialization for Primitives
(4 answers)
Closed 5 years ago.
Recently I saw a quite old code in C++, where int var(12) was used instead of int var=12. Why does it work? And should I avoid writing this style of declaration?
There are three ways of initializing variables are valid in C++.
type identifier = initial_value;
For example, to declare a variable of type int called x and initialize it to a value of zero from the same moment it is declared, we can write:
int a=5; // initial value: 5
type identifier (initial_value);
A second method, known as constructor initialization (introduced by the C++ language), encloses the initial value between parentheses (()):
int b(3); // initial value: 3
type identifier {initial_value};
Finally, a third method, known as uniform initialization, similar to the above, but using curly braces ({}) instead of parentheses (this was introduced by the revision of the C++ standard, in 2011):
int c{2}; // initial value: 2
You should check Documentation section Initialization of variables
This question already has answers here:
Is there a difference between copy initialization and direct initialization?
(9 answers)
Direct Initialization vs Copy Initialization for Primitives
(4 answers)
Closed 9 years ago.
I read the following code in c++:
bool result(false);
is result initialized as false?
but are there any benefits to do it instead of:
bool result = false;
can anyone help?