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# 1  
Old 09-24-2009
Explain a block of code:
Hi, I have this block in a code and I need to know it's meaning:

Code:
bool selectEvents = config.get("selectEvents",false);
  if (selectEvents) {
    ifstream in("events");
    while (in) {
      int run, evt;
      in >> run >> evt;
      if (in.eof()) break;
      selectedEvents.insert(make_pair(run,evt));
    }
    cout << "select " << selectedEvents.size() << " events" << endl;
  }

The statements I really need to know their meanings are the first one, which starts with bool and the one which starts with selectedEvents.insert().

I will appreciate any help,

eager
# 2  
Old 09-24-2009
Some of it we can only guess since it uses functions defined elsewhere, but here goes:

Code:
// Try to get the configuration value 'selectEvents'
bool selectEvents = config.get("selectEvents",false);
  // If the configuration value is true
  if (selectEvents) {
    // Open the file 'events'
    ifstream in("events");
    // While in still has more data to be read:
    while (in) {
      int run, evt;
      // Read two integers from the file
      in >> run >> evt;
      // If we couldn't read both, quit the loop right here
      if (in.eof()) break;
      // Otherwise, insert the new event into selectedEvents.
      selectedEvents.insert(make_pair(run,evt));
    }
    // Print the number of events stored in selectedEvents.
    cout << "select " << selectedEvents.size() << " events" << endl;
  }

We can't tell what selectedEvents actually is from this code snippet since it doesn't declare it anyway, it just uses it, but it's some sort of container, maybe a list. I can't guess what this 'config' function (or member, or whatever it is) comes from.
# 3  
Old 09-24-2009
Excellent!

So this line here:
bool selectEvents = config.get("selectEvents",false);

means selectEvents is of type bool, and it is equal to the outcome of the get() member. Now a small question:
What is the meaning of this format:
function("name", false)? what is the meaning of false here? does it mean if "name is not there"?

eager

PS.

All your guesses are right, it is a container. I am not able to post the whole code though Smilie But I am sure if I have your C++ knowledge, I could/can make miracles Smilie
# 4  
Old 09-25-2009
Quote:
Originally Posted by eager2no
So this line here:
bool selectEvents = config.get("selectEvents",false);

means selectEvents is of type bool, and it is equal to the outcome of the get() member. Now a small question:
What is the meaning of this format:
function("name", false)? what is the meaning of false here? does it mean if "name is not there"?
Perhaps, it could mean this

get (char* str, bool bAlwaysCreate)

i.e. if str is not present in config, create it and add it to the container.
# 5  
Old 09-25-2009
Quote:
Originally Posted by eager2no
Excellent!

So this line here:
bool selectEvents = config.get("selectEvents",false);

means selectEvents is of type bool, and it is equal to the outcome of the get() member. Now a small question:
What is the meaning of this format:
function("name", false)? what is the meaning of false here? does it mean if "name is not there"?
It might be what vino says. It might be a default value(what to return if the config value does not exist). It might be a useless stub for a feature not yet implemented. Without the function definition(or even its header) we'd only be guessing.
# 6  
Old 09-25-2009
Thank you all so much. I am really happy I am here in this nice forum.
Again, apologies for not being able to have the code here.

~eager
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