Lambda Behavior

[NiharRNanda]

Hi All ,
I am trying to learn Lambda in CPP.

With the following code I am expecting an output

Hello World!

#include <iostream>
using namespace std;

int main()
{
    []() {
        cout <<"Hello World!\n";
    };
    return 0;
}

but I am a getting blank screen.

I tried running the above code in visual studio (16.4.2) and also online at online gdb.com .On both occasions no result.

My debugger says :

The breakpoint will not currently be hit .No executable code of the debugger's target code is associated with this line .

Can anyone suggest ,why it is getting skipped?

Regards

[kbw]

You define a lamda, but never actually execute the code.

[Repeater]

As KBW says, you define a lambda, but you don't call it.

Your question is analogous to this:

Why isn't the function being called?

#include <iostream>
using namespace std;

void function()
{
  cout << "Hello World!\n";
}

int main()
{
    return 0;
}

You can call an anonymous lambda immediately after defining it:

#include <iostream>
using namespace std;

int main()
{
    []() {
        cout <<"Hello World!\n";
    }();  // NOTE ()
    return 0;
}

or you can give it a name and call it when you like:

#include <iostream>
using namespace std;

int main()
{
    auto lambda = []() {
        cout <<"Hello World!\n";
    };
    
    cout << "Now call:";
    lambda();
    return 0;
}

[NiharRNanda]

Thx All ,

My bad , I forgot that end of the day its a function and needs to be called .