C++ Address Book

[The Shadows]

Hi, I have to write an address book using structs for a class. I have 90% of the code done, but I am having trouble ordering it. It is supposed to read in 10 entries from a file and then sort them by last name. All the information also has to be swapped. I am using Microsoft VC++ 6. I would appreciate any input on what might be wrong with this program. Thanks for the help. :)

#include <iostream>
#include <string>
#include <fstream>
#include <algorithm>
using namespace std;
struct student
{
 string first_name;
 string last_name;
 string phone_number;
 string age;
 int month;
 int day;
 int year;
};
student log[100];
//double uslessfunction1(student log[].first_name,student log[].last_name,student log[].phone_number);
void uslessfunction1(student log[],ifstream infile,int x);
//double uslessfunction2(student log[].age,student log[].month,student log[].day,student log[].year);
void uslessfunction2(student log[],ifstream infile,int x);
void main()
{
 double num=0,x=0,counter=0;
 ifstream infile;
 ofstream outfile;
 infile.open("database.txt");
 outfile.open("output.txt");
 while(!infile.eof()){
 { counter=counter+1;
 
//  uslessfunction1(log[].first_name,log[].last_name,log[].phone_number);
  uslessfunction1(log[x],infile,x);
//  uslessfunction2(log[].age,log[].month,log[].day,log[].year);
  uslessfunction2(log[x],infile,x);
  x=x+1;
 }
 
 for (x=0;x<counter;x++)
  sort(log[x].first_name,log[x].first_name,10);
 for (x=0;x<counter;x++)
  outfile<<log[x].last_name<<", "<<log.first_name<<endl<<log[x].phone_number<<endl<<log[x].month<<"/"<<log[x].day<<"/"<<log[x].year<<endl;
 
}
//double uslessfunction1(student log[].first_name,student log[].last_name,student log[].phone_number)
void uslessfunction1(student log[],ifstream infile,int x)
{
 infile>>log[x].first_name;
 infile>>log[x].last_name;
 infile>>log[x].phone_number;
}
//double uslessfunction2(student log[].age,student log[].month,student log[].day,student log[].year)
void uslessfunction2(student log[],ifstream infile,int x)
{
 infile>>log[x].age;
 infile>>log[x].month,log[x].day,log[x].year;
}

[The Shadows]

Just incase anyone is having the same problem, I got it after much work. I guess my inputs on the date were wrong, causing traumatic memory problems :)

If anyone is interested in the code, here it is

#include <iostream>
#include <string>
#include <fstream>
#include <algorithm>
using namespace std;
struct student
{
 string first_name;
 string last_name;
 string phone_number;
 string age;
 string month;
 string day;
 string year;
};
student log[100];
void main()
{
 int num=0,x=0,counter=0,y=0;
 student temp;
 ifstream infile;
 ofstream outfile;
 infile.open("database.txt");
 outfile.open("output.txt");
 while(!infile.eof())
 { counter=counter+1;
 
  infile>>log[x].first_name;
  infile>>log[x].last_name;
  infile>>log[x].phone_number;
  infile>>log[x].age;
  infile>>log[x].month;
  infile>>log[x].day;
  infile>>log[x].year;
  x=x+1;
 }
 for (x=0;x<counter;x++){
  for(y=x+1;y<10;y++){
   if (log[x].last_name > log[y].last_name){
	temp = log[x];
	log[x] = log[y];
	log[y] = temp;
   }
  }   
 }
 for (x=0;x<counter;x++)
  outfile<<log[x].last_name<<", "<<log[x].first_name<<endl<<log[x].phone_number<<endl<<log[x].month<<"/"<<log[x].day<<"/"<<log[x].year<<endl<<endl;
}

[BlackDice]

just wanted to let you know that you've re-discovered the 'bubble sort' algorithm. The code looks fine except that you should use 'x += 1' instead of 'x = x + 1' -- it's faster. you may not see much of a difference in a loop of that many iterations or with numbers, but it'll really help with strings and loops with more iterations. Besides, it's faster to type! Keep up the good work

[infamous]

it is faster to type but there's no difference in the code generated, test it and see for yourself.

[BlackDice]

According to this book I have, 'C++ for Game Programmers' published by Charles River Media, it says that it's a lot faster when dealing with CString operations, I will go back to it and make sure, but I'm pretty sure now. I haven't tested it, but I was taking the book's word. But I appreciate your comment; that makes me investigate!!

[infamous]

ok, if you're talking about something high level like that it may be true, but for say some simple integer x it makes no difference in the generated asm. :)

[bonethugs]

please help me in making address book