Thread: Need help to get rid of segmentation fault

The sample line of the file "RedwoodBaySeismicEventList.data" looks like this :

[Text]

Alpha:01232012:0100:2.7

[/Text]

Note:
"Alpha" represents ID
"01232012" represents Date
"0100" represents Hour
"2.7" represents Magnitude

Also, sorry I forgot to indent the code earlier. So, here is the indented code below:

Code:

    #include <iostream>
    #include <fstream>
    #include <string>
    #include <vector>
    #include <sstream>
    using namespace std;
    
    //Define a class to represent each Seismic Activity measurement event...
    
        class RedwoodBaySeismicData  {
          string LocationID;   //This is the station that owns this piece of data…
          string Date;     //The date that the values were collected…
          string Time;    //The time of day that the values were collected…
          double SeismicSize;  //Magnitude of Earthquake
          
        
        public:
          RedwoodBaySeismicData();
          RedwoodBaySeismicData(string, string, string, double);
        
          //The first group of member functions are used to change values...
          //Functions are defined in the form of inlines.
        
          void SetID(string ID)     { LocationID = ID; }
          void SetDate(string Day)   { Date = Day; }
          void SetTime(string Hour)   { Time = Hour; }
          void SetSeismicSize(double Magnitude) {SeismicSize = Magnitude; }
          
        
          //The second group allows controlled access to individual value in the class...
        
          string GetID()    { return LocationID; }
          string GetDate()   {return Date; }
          string GetTime()   {return Time; }
          double GetSeismicSize() { return SeismicSize;}  
          
         
        
        };
        
        
        
        //The default constructor sets the private variable members to a harmless value...
        
        RedwoodBaySeismicData::RedwoodBaySeismicData()
        {
         LocationID = "";
         Date = "";
         Time = "";
         SeismicSize = 0.0;
         
        }
        
        //This initializing  constructor allows you to create a object with value already set...
        
         RedwoodBaySeismicData::RedwoodBaySeismicData(string ID, string Day, string Hour, double Magnitude)
        {
         LocationID = ID;
         Date = Day;
         Time = Hour;
         SeismicSize = Magnitude;
         
        }
     
         class RedwoodBayDataList  {
         vector<RedwoodBaySeismicData> RedwoodBayDataSpots;  //Create a collection of location information...
            string FileName ;
         public:
         RedwoodBayDataList()  {FileName = "RedwoodBaySeismicEventList.data";}
        
            
        void PostSeismicInfo();
            
        };
         
     
     
        //Allow the user to post the values for each location...
    
        void RedwoodBayDataList::PostSeismicInfo()
        {
         int K;
         string Line, ID, Date, Hour;
         double Magnitude;
         fstream InFile("RedwoodBaySeismicEventList.data", ios::in);
         //...then get the values for each location...
         RedwoodBaySeismicData Buffer;
     
            cout << "\n\t=============================================================" << endl;  //This section is the report...it's really all about the formatting...
            cout << "\tWeekly Report" << endl;
            cout << "\t===============================================================" << endl;
            cout << "\tLocation\tDate\tHour\tMagnitude" << endl;
            cout << "\t===============================================================" << endl;
     
    
         for(size_t K = 0; K < RedwoodBayDataSpots.size(); ++K)  {
                  
          getline(InFile, Line);
          ID = Line.substr(0,4);
          Date =  Line.substr(6,7);
          Hour = Line.substr(9,3);
          istringstream buf(Line.substr(5,2));
          buf>> Magnitude;
            
          Buffer.SetID(ID);    //Use these values to load the Buffer record...
          Buffer.SetDate(Date); 
          Buffer.SetTime(Hour);
          Buffer.SetSeismicSize(Magnitude);
          RedwoodBayDataSpots.push_back(Buffer);
      
         
          RedwoodBayDataSpots[K].SetID(ID);
          RedwoodBayDataSpots[K].SetDate(Date);
          RedwoodBayDataSpots[K].SetTime(Hour);
          RedwoodBayDataSpots[K].SetSeismicSize(Magnitude);  
          cout << "\t" << RedwoodBayDataSpots[K].GetID() << "\t" << RedwoodBayDataSpots[K].GetDate() << "\t" << RedwoodBayDataSpots[K].GetTime() << "\t"  << RedwoodBayDataSpots[K].GetSeismicSize();
           }
          cout << "\t===============================================================\n\n" << endl;
    
     
           }
     
        
    
    //Declare the functions...
    
        void RunIT();
        void Menu();
         
        
        int main()
        {
         RunIT();
        }
    
    //This function implements a simple command processor...
    
        void RunIT()
        {
         RedwoodBayDataList RedwoodBayDataSpots;
         string Command = "";
    
         while(Command != "Quit")  {
          Menu();
          cout << "Command: ";
          getline(cin, Command);
     
          if(Command == "Report")
           RedwoodBayDataSpots.PostSeismicInfo();
         }
         }
    
    //This function tells the user what he or she can do...
    
        void Menu()
        {
         cout << "Choices...................................................." << endl;
         cout << "-----------------------------------------------------------" << endl;
         cout << "\tReport...displays the  report." << endl;
         cout << "\tQuit.....exits the program." << endl;
         cout << "-----------------------------------------------------------" << endl;
         }

In your PostSeismicInfo() function in the following line:

Code:

  for(size_t K = 0; K < RedwoodBayDataSpots.size(); ++K)  {

When you first encounter this loop your vector contains zero items so K will be equal to the size, therefore the loop will never execute. Normally when you are reading an input file you use a while() loop and push the data into the vector after you read the line of information.


Also because a std::string is a class to construct an empty instance you don't want to use the assignment operator. For example:

Code:

   std::string test = ""; // This is not necessary.
   std::string test;       // This is the proper way to construct an empty string.

When you use the assignment operator you cause the compiler to do extra steps, for example calling the copy constructor. And in a class constructor you don't actually need to construct an empty string member because the default constructor for a string is an empty string.


Jim

Hi everyone. As per the advice, I have modified my code again. Now, I am using while loop to read the data from the file. However, my programme is still not running. Whenever I try to run the programme the dialog box appears and says "un.exe" has stopped working. By the way, I am usin DEV C++. Also, here is the modified version of the code:

Code:

    #include <iostream>
    #include <fstream>
    #include <string>
    #include <vector>
    #include <sstream>
    using namespace std;
    
    //Define a class to represent each Seismic Activity measurement event...
    
        class RedwoodBaySeismicData  
        {
          string LocationID;   //This is the station that owns this piece of data…
          string Date;     //The date that the values were collected…
          string Time;    //The time of day that the values were collected…
          double SeismicSize;  //Magnitude of Earthquake
          
        
        public:
          RedwoodBaySeismicData();
          RedwoodBaySeismicData(string, string, string, double);
        
          //The first group of member functions are used to change values...
          //Functions are defined in the form of inlines.
        
          void SetID(string ID)     { LocationID = ID; }
          void SetDate(string Day)   { Date = Day; }
          void SetTime(string Hour)   { Time = Hour; }
          void SetSeismicSize(double Magnitude) {SeismicSize = Magnitude; }
          
        
          //The second group allows controlled access to individual value in the class...
        
          string GetID()    { return LocationID; }
          string GetDate()   {return Date; }
          string GetTime()   {return Time; }
          double GetSeismicSize() { return SeismicSize;}  
          
         
        
        };
        
        
        
        //The default constructor sets the private variable members to a harmless value...
        
        RedwoodBaySeismicData::RedwoodBaySeismicData()
        {
         LocationID;
         Date;
         Time;
         SeismicSize = 0.0;
         
        }
        
        //This initializing  constructor allows you to create a object with value already set...
        
         RedwoodBaySeismicData::RedwoodBaySeismicData(string ID, string Day, string Hour, double Magnitude)
        {
         LocationID = ID;
         Date = Day;
         Time = Hour;
         SeismicSize = Magnitude;
         
        }
     
        class RedwoodBayDataList 
        {
             vector<RedwoodBaySeismicData> RedwoodBayDataSpots;  //Create a collection of location information...
             string FileName ;
        public:
             RedwoodBayDataList()  {FileName = "RedwoodBaySeismicEventList.data";}
            
                
             void PostSeismicInfo();
            
        };
         
     
     
        //Allow the user to post the values for each location...
    
            void RedwoodBayDataList::PostSeismicInfo()
        {
             int K;
             string Line, ID, Date, Hour;
             double Magnitude;
             fstream InFile("RedwoodBaySeismicEventList.data", ios::in);
             //...then get the values for each location...
             RedwoodBaySeismicData Buffer;
     
             cout << "\n\t=============================================================" << endl;  //This section is the report...it's really all about the formatting...
             cout << "\tWeekly Report" << endl;
             cout << "\t===============================================================" << endl;
             cout << "\tLocation\tDate\tHour\tMagnitude" << endl;
             cout << "\t===============================================================" << endl;
     
             
                      
              while (!InFile.eof())            
                  
         { 
              getline(InFile, Line);
              ID = Line.substr(0,4);
              Date =  Line.substr(6,7);
              Hour = Line.substr(9,3);
              istringstream buf(Line.substr(5,2));
              buf>> Magnitude;
            
              Buffer.SetID(ID);    //Use these values to load the Buffer record...
              Buffer.SetDate(Date); 
              Buffer.SetTime(Hour);
              Buffer.SetSeismicSize(Magnitude);
              RedwoodBayDataSpots.push_back(Buffer);
      
              for(K = 0 ; K < RedwoodBayDataSpots.size(); ++K)  
              {
              RedwoodBayDataSpots[K].SetID(ID);
              RedwoodBayDataSpots[K].SetDate(Date);
              RedwoodBayDataSpots[K].SetTime(Hour);
              RedwoodBayDataSpots[K].SetSeismicSize(Magnitude);  
              cout << "\t" << RedwoodBayDataSpots[K].GetID() << "\t" << RedwoodBayDataSpots[K].GetDate() << "\t" << RedwoodBayDataSpots[K].GetTime() << "\t"  << RedwoodBayDataSpots[K].GetSeismicSize();
              }
              cout << "\t===============================================================\n\n" << endl;
              }
              InFile.close();
    
    
          }
        
    
    //Declare the functions...
    
          void RunIT();
          void Menu();
         
       
          int main()
          {
          RunIT();
          }
    
    //This function implements a simple command processor...
    
          void RunIT()
          {
          RedwoodBayDataList RedwoodBayDataSpots;
          string Command;
    
          while(Command != "Quit")  {
          Menu();
          cout << "Command: ";
          getline(cin, Command);
     
           if(Command == "Report")
           RedwoodBayDataSpots.PostSeismicInfo();
           }
           }
    
    //This function tells the user what he or she can do...
    
          void Menu()
          {
          cout << "Choices...................................................." << endl;
          cout << "-----------------------------------------------------------" << endl;
          cout << "\tReport...displays the  report." << endl;
          cout << "\tQuit.....exits the program." << endl;
          cout << "-----------------------------------------------------------" << endl;
          }

As always, I would greatly appreciate any suggestions.