What is a lambda expression in C 11

0 votes
In C++11, what is a lambda expression?

When would I put one to use?

What kind of problem do they tackle that couldn't be solved before they were introduced?

A few use cases and examples would be helpful.
Jun 15 in C++ by Nicholas
• 4,720 points
25 views

1 answer to this question.

0 votes

In C++11, what is a lambda expression?

A: It's the object of an autogenerated class with overloading operator() const under the hood. 

Closure is a type of object that is produced by the compiler. 

This 'closure' idea is similar to C++11's bind notion. 

Lambdas, on the other hand, usually produce better code. 

Full inlining is also possible with calls through closures.

Q: When do you think I'd utilise one?

A: Define "simple and tiny logic" and request that the compiler generate the code from the preceding question. 

You tell the compiler the expressions you wish to be inside the operator (). 

The compiler will produce everything else for you.

Q: What kind of problem do they tackle that couldn't be solved before they were introduced?

A: It's some form of syntactic sugar, like using operators instead of functions for custom add, subtract, and other operations...

However, wrapping 1-3 lines of genuine logic to some classes, and so on, saves additional lines of needless code! 

Some engineers believe that if the number of lines is reduced, there is a lower likelihood of mistakes (which I agree with).

Example of usage

auto x = [=](int arg1){printf("%i", arg1); };
void(*f)(int) = x;
f(1);
x(1);
answered Jun 15 by Damon
• 4,760 points

Related Questions In C++

0 votes
1 answer

What is a Class and Object in C++?

A Class is like a blueprint, an ...READ MORE

answered Jun 21 in C++ by Damon
• 4,760 points
19 views
0 votes
0 answers

What is the fastest way to transpose a matrix in C++?

I have a reasonably large matrix that I need to transpose.  Assume, for example, that my matrix is a b c d e f g h ...READ MORE

Jul 15 in C++ by Nicholas
• 4,720 points
9 views
0 votes
1 answer

What data structure is inside std::map in C++?

An associative container is std::map. The standard's ...READ MORE

answered May 31 in C++ by Damon
• 4,760 points
33 views
0 votes
0 answers

What is the C++ function to raise a number to a power?

What's the best way to raise a n ...READ MORE

Jun 1 in C++ by Nicholas
• 4,720 points
24 views
0 votes
1 answer

What is a smart pointer and when should I use one?

A smart pointer is similar to a ...READ MORE

answered Jun 2 in C++ by Damon
• 4,760 points
17 views
0 votes
0 answers

Is hiding implementation detail Encapsulation or Abstraction?

I have seen some people defining abstraction ...READ MORE

May 6 in Java by narikkadan
• 11,280 points
123 views
0 votes
1 answer

What is this weird colon-member (" : ") syntax in the constructor?

Foo(int num): bar(num) In C++, this is known as a Member Initializer List. Simply put, it sets the value of your member bar to num. There is a significant difference between initializing a member with the Member initializer list and assigning a value to it within the function Object() { [native code] } body. When you use the Member initializer list to initialise fields, the constructors are only called once, and the object is constructed and initialised in a single operation. If you use assignment, the fields will be initialised with default constructors and then reassigned with actual values (via the assignment operator). As you can see, there is an extra overhead of creation and assignment in the latter, which may be significant for user defined classes. Cost of Member Initialization =Object ...READ MORE

answered May 27 in Others by Damon
• 4,760 points
42 views
0 votes
1 answer

Why would anyone use set instead of unordered_set?

Unordered sets must compensate for their O(1) ...READ MORE

answered Jun 1 in C++ by Damon
• 4,760 points
51 views
0 votes
1 answer

In C++, what is a virtual base class?

When employing multiple inheritance, virtual base classes are used to prevent several "instances" of a particular class from appearing in an inheritance hierarchy. Consider the following example: class A { public: void Foo() {} ...READ MORE

answered Jun 10 in C++ by Damon
• 4,760 points
20 views
0 votes
1 answer

What is the best way to use a HashMap in C++?

The ordered and unordered map containers (std::map and std::unordered map) are included in the standard library.  The items in an ordered map are sorted by key, and insert and access are in O (log n).  For ordered maps, the standard library often use red black trees.  However, this is only an implementation detail.  Insert and access are in O in an unordered map (1).  It is simply another term for a hashtable. An illustration using (ordered) std::map: #include <map> #include <iostream> #include <cassert> int main(int argc, char ...READ MORE

answered Jun 10 in C++ by Damon
• 4,760 points
40 views
webinar REGISTER FOR FREE WEBINAR X
Send OTP
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP