Get index in C++11 foreach loop

Question

Is there a convenient way to get the index of the current container entry in a C++11 foreach loop, like enumerate in python:

for idx, obj in enu         


        

Answer 1

What about a simple solution like:

int counter=0;
for (auto &val: container)
{
    makeStuff(val, counter);

    counter++;
}

You could make a bit more "difficult" to add code after the counter by adding a scope:

int counter=0;
for (auto &val: container)
{{
    makeStuff(val, counter); 
}counter++;}

As @graham.reeds pointed, normal for loop is also a solution, that could be as fast:

int counter=0;
for (auto it=container.begin(); it!=container.end(); ++it, ++counter)
{
    makeStuff(val, counter);
}

And finally, a alternative way using algorithm:

int counter = 0;
std::for_each(container.begin(), container.end(), [&counter](int &val){ 
    makeStuff(val, counter++);
});

Note: the order between range loop and normal loop is guaranteed by the standard 6.5.4. Meaning the counter is able to be coherent with the position in the container.