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[Virex]

You can use an iterator for that, see the following example: http://www.cplusplus.com/reference/map/map/begin/

[MagmaMcFry]

Try this:

Code: [Select]

for (auto entry : data) {
  string key = entry.first;
  int value = entry.second;
  // your code here
}


[MrWillsauce]

Don't you need 3 conditions for a for loop or something? This isn't working.

[Mego]

Don't you need 3 conditions for a for loop or something? This isn't working.

That's a range-based for loop. It requires C++11 support to be used.

[MrWillsauce]

So how would I do what I want to do with an earlier version of C++?

[Telgin]

Not certain this code is correct syntax and I have no compiler installed on this computer, but something like this should work:

Code: [Select]

map<string, int>::iterator it;

for (it = data.begin(); it != data.end(); it++) {
    // Do whatever you need to do with the data value.  it->first is the key, it->second is the value
    cout << it->second;
}

It's been a little while since I've worked with iterators, but I'm pretty sure it should fit that pattern pretty closely.

To explain the code: iterators are a class that abstract accessing elements of STL containers like maps and vectors.  They use operator overloading to make it possible to advance them by the ++ operator, so you can treat them almost like an integer in that respect.  The containers have methods for getting iterators for the beginning and end of the container (begin() and end()).

[MrWillsauce]

Thank you very much.

So, I've written the basic skeleton of the program http://pastebin.com/bTnBHej4, but when I try to compile I get the error "debug assertion failed... vector subscript out of range". Does anyone know what that's about?

[Skyrunner]

It means you are trying to access a vector element that doesn't exist. Eg, for a vector of length 10 you attempt to access the 11th element.

Also: try searching the internet with the error message. Nine out of ten Stack Overflow has the answer. XD

[MagmaMcFry]

So, I've written the basic skeleton of the program http://pastebin.com/bTnBHej4, but when I try to compile I get the error "debug assertion failed... vector subscript out of range". Does anyone know what that's about?

Did that error come with a line number?

[Skyrunner]

Data is c++ <string, int> map.

Assuming data is a dictionary can't you just do: (python code, but that's basically pseudo-code so you'll understand )

Code: [Select]

for key in data:
    print(key, data[key])

Try this:

Code: [Select]

for (auto entry : data) {
  string key = entry.first;
  int value = entry.second;
  // your code here
}


It might just be MSVS, but

Code: [Select]

for each (auto entry in data)
{
  string key = entry.first;
  int value = entry.second;
  // your code here
}
seems to work. I've used it extensively in my AI's code, and it's a lot more intuitive than for ( x : y)... but that just might be me.

[MagmaMcFry]

Looks like that's not part of the C++11 standard.

[Skyrunner]

That makes sense. It's code from C# that happens to work exactly the same in C++. I imagine the msvc compiler replaces all for each with for (x : y).

[ECrownofFire]

Yeah, don't do that. Ever. Non-standard extensions are evil.

Seriously, you'll be kicking yourself if you ever want to compile that with GCC or Clang.

[Skyrunner]

Yeah, don't do that. Ever. Non-standard extensions are evil.

Seriously, you'll be kicking yourself if you ever want to compile that with GCC or Clang.

Well, that instance is really easy and trivial to fix. Just replace all for each with ( x : y) when I want to compile it on gcc.

[MrWillsauce]

So, I've written the basic skeleton of the program http://pastebin.com/bTnBHej4, but when I try to compile I get the error "debug assertion failed... vector subscript out of range". Does anyone know what that's about?

Did that error come with a line number?

Line:932