Sorting a deque with class objects

Question

I have a question about sorting a deque with class objects. So I have one deque called "rq" which holds, multiple types of data. I want to sort the deque by comparing the TAU values. However, I keep getting insane compiler errors when trying to sort the deque. Below is the the function I tried to do in order to compare TAU values and sort the deque. How would i go about solving this problem?

 deque<system>rq 
 //and so on
 struct tauSort
 {
     bool operator ()( system &a,  system  &b)
     {              
         return a.getTau() < b.getTau();        
     } 
 }

 //Blah Blah
 system sorting;
 sort(rq.begin(), rq.end(), sorting)

Answer 1

This:

system sorting;

should be this:

tauSort sorting;

because you want to pass the sorting functor, not a system object. And you are forgetting a semicolon at the end of the sort statement too.

You can also simply do:

sort(rq.begin(), rq.end(), tauSort());

Not to mention that you can pass the systems by constant reference in your function, since you don't need to modify them. And it's better for you to make the operator() const as well:

bool operator ()(system const& a,  system const& b) const { … }