Thread: Problem Creating Functions

Hello,

I have the following code all written and working properly:

Code:

#include <iostream>
#include <fstream>
#include <string>
#include <list>
#include <queue>
using namespace std;

void updateRun();
void updateReady();
void updateWait();

int main () {
  ifstream infile("in_file.txt");
  ifstream event("events.txt");
  
  list<string> vec;
  list<string> tempPro;
  
  queue<string> run;
  queue<string> ready;
  queue<string> wait;
  
  if (!infile || !event) {
    cerr << "error: unable to open input file!\n";
    return -1;
  }

  string word;
  while (infile >> word) {
      vec.push_back(word);
      string tempEl;
      if (word == "running") {
            tempEl = tempPro.front();
            tempPro.pop_front();
            run.push(tempEl);
      }
      else if (word == "ready") {
            tempEl = tempPro.front();
            tempPro.pop_front();
            ready.push(tempEl);
      }
      else if (word == "waiting") {
            tempEl = tempPro.front();
            tempPro.pop_front();
            wait.push(tempEl);
      }
      else tempPro.push_front(word);
    
      if (word == "running" || word == "ready" || word == "waiting") {  
          int runSize = run.size();
          int readySize = ready.size();
          int waitSize = wait.size();
      
          cout << "Running: ";
          while (runSize != 0) {
              string running = run.front();
              cout << running << " ";
              run.pop();
              run.push(running);
              runSize--;
          }
          cout << endl;
          cout << "Ready: ";
          while (readySize != 0) {
              string readyToGo = ready.front();
              cout << readyToGo << " ";
              ready.pop();
              ready.push(readyToGo);
              readySize--;
          }
          cout << endl;
          cout << "Waiting: ";
          while (waitSize != 0) {
              string waiting = wait.front();
              cout << waiting << " ";
              wait.pop();
              wait.push(waiting);
              waitSize--;
          }
          cout << endl;
          cout << endl;
      }
  }
  
  string word2;
  int eventNum = 1;
  
  while (event >> word2) {
    if (word2 == "1") {
        string elem1 = run.front();
        if (ready.size() != 0 ) {
                string toRun1 = ready.front();
                ready.pop();
                run.push(toRun1);
        }
    }
    else if (word2 == "2") {
        string elem2 = run.front();
        run.pop();
        wait.push(elem2);
        if (ready.size() != 0) {
                string toRun2 = ready.front();
                ready.pop();
                run.push(toRun2);
        }
        else {
                string toRun2 = wait.front();
                wait.pop();
                run.push(toRun2);
        }
    }
    else if (word2 == "3") {
        string elem3 = wait.front();
        wait.pop();
        ready.push(elem3);
        if (ready.size() == 0 || run.size() == 1) {
                string toRun3 = ready.front();
                ready.pop();
                run.pop();
                run.push(toRun3);
        }
    }
    
    int runSize = run.size();
    int readySize = ready.size();
    int waitSize = wait.size();
  
    cout << endl;
    cout << "Event #" << eventNum << endl;
    cout << "Running: ";
    while (runSize != 0) {
        string running = run.front();
        cout << running << " ";
        run.pop();
        run.push(running);
        runSize--;
    }
    cout << endl;
    cout << "Ready: ";
    while (readySize != 0) {
        string readyToGo = ready.front();
        cout << readyToGo << " ";
        ready.pop();
        ready.push(readyToGo);
        readySize--;
    }
    cout << endl;
    cout << "Waiting: ";
    while (waitSize != 0) {
        string waiting = wait.front();
        cout << waiting << " ";
        wait.pop();
        wait.push(waiting);
        waitSize--;
    }
    cout << endl;
    eventNum++;
  }
  return 0;
}

What I want to do is to take the parts of the code in bold and make them into their own functions. I tried declaring the queue objects outside of the main function, but that gave me a compiler error. Can someone show me the code to make the functions out of those lines of code in bold?

Is there a reason you can't just make 3 functions of type void, put your code in there, and call those functions in place of your bold code?

I can't do that because it gives me an error saying that the queues that are used in that code are undeclared. For example, in the first bolded code, it says the queues ready and run are undeclared.

How would I go about making them global? Just declare them outside of the main function?

Ok, how would I write a function that takes them as arguments? I'm getting an error when I do it the way I think I'm supposed to do it. Sorry about all the questions but I'm new to C++.

Thanks, it works now! I wasn't putting the data type that the queue would hold in my arguments. One more question, this is just for my general knowledge, but what is the purpose of those ampersands in the arugments? Thanks.