What is the meaning of the two parts specified between parentheses in a range-based for loop, separated by a colon?
The first is an iterator, and the second is the increment value to be added to the iterator.
The first is a variable declaration that will hold an element in a sequence. The second is the sequence to traverse.
The first is the iterating variable. The second is an std::pair that specifies the range (start and end) in which the variable will iterate.
std::pair
The first is a container object. The second is an std::pair that specifies the range (start and end) in which the elements will be accessed within the loop.