Testing C++11 functional

func11.cpp

#include <iostream>
#include <string>
#include <functional>

using namespace std;

class TestScope
{
public:
    int val;
    TestScope()
    {
        val=0;
    }
    TestScope(int a)
    {
        val=a;
    }
    ~TestScope()
    {
        cout<<"Destroying!!!"<<endl;
    }
    TestScope& operator=(int a)
    {
        val=a;
        return *this;
    }
    void test()
    {
        cout<<val;
    }
};

int main()
{
    // Test recursive
    // use '&' to pass 'fibo' as reference.
    function<int (int)> fibo = [&](int n) -> int {
        if(n==1 || n==2)
            return 1;
        return fibo(n-1)+fibo(n-2);
    };
    
    cout<<fibo(8)<<endl;
    
    function<void()> tfunc;
    
    {
        TestScope test = 100;
        
        // Test passing by reference
        tfunc = [&]() {
            cout<< "test = ";
            test.test();
            cout<<endl;
        };
        
        test = 10000;
        
        tfunc();
    }
    
    // Test out of scope (this is the only test that fails)
    tfunc();
    
    return 0;
}

/* Result:
21
test = 10000
Destroying!!!
test = 10000
*/