How can I access local variables from inside a C++11 anonymous function?

Question

I\'m doing a simple normalization on a vector (weights), trying to make use of STL algorithms to make the code as clean as possible (I realize this is pretty trivial with fo

Answer 1

You need to add tot to the "capture list":

float tot = std::accumulate(weights.begin(), weights.end(), 0);
std::transform(weights.begin(), weights.end(), [tot](float x)->float{return(x/tot);});

Alternatively you can use a capture-default to capture tot implicitly:

float tot = std::accumulate(weights.begin(), weights.end(), 0);
std::transform(weights.begin(), weights.end(), [=](float x)->float{return(x/tot);});