Can I call a lambda without first assigning it to a variable?

Question

I'm learning how to use lambda functions. Why doesn't my last lambda run automatically if not assigned to a variable? All the previous ones work as expected.

#include "stdafx.h"
#include <iostream>
#include <thread>
using namespace std;
int main()
{
    std::thread t([]() {
        std::cout << "thread function\n";
    });
    std::cout << "main thread\n";
    t.join();

    auto a = []() -> int {
        return 1 + 2;
    };
    int n = a();
    cout << n << endl;

    auto b = []() -> void {
        cout << "sup" << endl;
    };
    b();

    //why doesn't this run automatically?
    []() -> void {
        cout << "hellur!" << endl;
    };

    return 0;
}

Can I call a lambda without first assigning it to a variable? — nhershy, Mar 11 '18 at 23:35
Possible duplicate of [How to immediately invoke a C++ lambda?](https://stackoverflow.com/questions/44868369/how-to-immediately-invoke-a-c-lambda) — Raymond Chen, Mar 12 '18 at 00:24
... why would you want to do this out of curiosity? Why not simply include the actual code there instead of a lambda? — Steve, Mar 12 '18 at 03:09

score 1 · Accepted Answer · answered Mar 11 '18 at 23:45

1

Solution:

[]() -> void {
    cout << "hellur!" << endl;
}();

answered Mar 11 '18 at 23:45

nhershy

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Can I call a lambda without first assigning it to a variable?

1 Answers1