Thread: delete invalid data from an array

Hi i have a program that reads data from a file.. if the quantity or date is wrong it would ignore that entry completely for further comparison how would i go about putting only valid types into the array..

text file :

Code:

10212 Nescafe 20 1/12/05
13114 Pepsi -11 10/27/05

Code:

#include <iostream>
#include <fstream>
#include <string>

#define SIZE 100
using namespace std;

class store
{
      public:
             int custnum;
             string product;
             int quantity;
             char tmp[20];
             char month[80];
             char day[80];
             char year[80];
};

store STORE1[SIZE];

int num_lines(char name[]) // this function counts the number of lines in file
{
char templine[100];
int line=0;
    fstream in_file(name,ios::in);
    if(!in_file)
    {
      cout << "error opening file";
      exit(1);
    }
    while (!in_file.eof()){
      in_file.getline(templine,100);
      line++;
      
                }
                in_file.close();
                return line;

}

void period()
{

}

void all()
{
     cout << "THIS IS A TEST TO SEE IF THE FUNCTION WORKS" << endl;
}

void menu()
{
     int option,line,tmp;     
     char name[20],c;
     cout << "Enter name of file to load:";
     cin >> name;
     line = num_lines(name);

     fstream in_file(name,ios::in);
     if(!in_file)
     {
         cout << "error opening file";
         exit(1);
     }
     for(int x=0;x<line;x++)
     {
             in_file >> STORE1[x].custnum;
             in_file >> STORE1[x].product;
             in_file >> STORE1[x].quantity;
             in_file.getline(STORE1[x].month,100,'/');
             in_file.getline(STORE1[x].day,100,'/');
             in_file >> STORE1[x].year;
             in_file.ignore(80,'\n'); 
             tmp = atoi(STORE1[x].month);
             if(tmp > 12 || tmp < 1 || strlen(STORE1[x].month) < 3)
                      cout << "Line " << x << " has invalid date" << endl; 
             if(STORE1[x].quantity < 0) 
                     cout << "Line " << x << " has invalid quantity " << endl; 
      }  



     in_file.close(); 
     cout << "The month is " << STORE1[1].year << endl;

     
     do {
   
     cout << "Please select a menu option:" << endl;
     cout << "1)Product sales in a given period" << endl;
     cout << "2)Information about all sales" << endl;
     cout << "3)Quit the program" << endl;
     cout << "Option (1,2,3):";
     cin >> option;
   
     switch(option) {
     case 1: 
          period();
          break;
     case 2:
          all();
          break;
          }
   
     } while(option!=3);
}

int main()
{
    menu();
    system("PAUSE");
    return 0;   
}

while (!in_file.eof())

Bad, bad, bad. What happens if an error occurs while you are reading from the file which prevents you from reading any more data from the file? Will your loop ever end?

i modified it to this

Code:

     for(int x=0;x<line;x++)
     {
             in_file >> STORE1[x].custnum;
             in_file >> STORE1[x].product;
             in_file >> STORE1[x].quantity;
             in_file.getline(STORE1[x].month,100,'/');
             in_file.getline(STORE1[x].day,100,'/');
             in_file >> STORE1[x].year;
             in_file.ignore(80,'\n'); 
             tmp = atoi(STORE1[x].month);
             if(tmp > 12 || tmp < 1 || strlen(STORE1[x].month) < 3)
                      cout << "Line " << x << " has invalid date" << endl; 
             if(STORE1[x].quantity < 0) 
                     cout << "Line " << x << " has invalid quantity " << endl; 
      }

but it will store the array where the value of x is.. i want valid data to be stored 0,1,2 not 1,4,5 etc...