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fstream isnt getting the data right

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•

Join Date: May 2005

Posts: 232

Reputation: Dogtree is an unknown quantity at this point

Solved Threads: 3

Dogtree

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Posting Whiz in Training

Re: fstream isnt getting the data right

#11

May 18th, 2005

When you swap the name array, you'll have to swap all of the other arrays along with it, since each array is a unique object. A good alternative is to stuff everything in an structure and then sort an array of structs:

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 C++ Syntax (Toggle Plain Text) 
struct record {
  string name;
  // ...
} rec[N];
struct record {
  string name;
  // ...
} rec[N];

That would save you a lot of work because you can treat a record as a single unit rather than an index in a bunch of arrays.

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Join Date: Mar 2005

Posts: 16

Reputation: Tetsu is an unknown quantity at this point

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Tetsu

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Newbie Poster

Re: fstream isnt getting the data right

#12

May 19th, 2005

But I think I need to use the arrays because there are 30 records. I need to sort the records by names. I got the Last name down but what should I do to get that person other records along with his last name?

I try this but it would'nt display the first name

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(Toggle Plain Text)

void sortLastname(int a)
{
	string temp = string();
	string temp2 = string();
	char pick = char();

	for(int i=0; i<30; i++) 
	{
		for (int j=0; j<30-i; j++)
		{
			if (lname[j] > lname[j+1])	// compare the two neighbors 
			{  
				temp = lname[j];         
				lname[j] = lname[j+1];	// swap lname[j] and lname[j+1]      
				lname[j+1] = temp;
				for(int q=0; q<30; q++) 
				{
					for (int w=0; w<30-i; w++)
					{
						if (fname[w] > fname[w+1])	// compare the two neighbors 
						{  
						temp = fname[j];         
						fname[w] = fname[w+1];	// swap fname[w] and fname[w+1]      
						fname[w+1] = temp2;
						}
					}
				}
			}	
		}
		cout << temp << " " <<temp2 <<endl;
		
		//cout << setw(5) << left <<  ID[i] << setw(10) << left << fname[i] << setw(12) << lname[i] << setw(2) << middlei[i] << setw(7) << state[i] << setw(5) << right << zip[i] << setw(6) << right << hrWork[i] << setw(8) << right << ratePhour[i]  << endl;
	}

•

Join Date: May 2005

Posts: 232

Reputation: Dogtree is an unknown quantity at this point

Solved Threads: 3

Dogtree

Offline

Posting Whiz in Training

Re: fstream isnt getting the data right

#13

May 19th, 2005

You're sorting by name, and name only. Just because a name goes in one spot doesn't mean the corresponding data goes in the same spot if you sort it too. This is basically what you're doing:

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 C++ Syntax (Toggle Plain Text) 
#include <algorithm>
#include <iostream>
#include <iterator>
 
template <typename T>
void bubble(T list[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list[j] < list[i])
        std::swap(list[i], list[j]);
    }
  }
}
 
int main()
{
  int a[] = {9,8,7,6,5,4,3,2,1,0};
  int b[] = {6,7,5,8,9,0,4,3,2,1};
 
  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
 
  bubble(a, 10);
 
  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
}
#include <algorithm>
#include <iostream>
#include <iterator>

template <typename T>
void bubble(T list[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list[j] < list[i])
        std::swap(list[i], list[j]);
    }
  }
}

int main()
{
  int a[] = {9,8,7,6,5,4,3,2,1,0};
  int b[] = {6,7,5,8,9,0,4,3,2,1};

  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';

  bubble(a, 10);

  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
}

To get it to work, you need to pass the other arrays and swap them too, but only use name in the test:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <algorithm>
#include <iostream>
#include <iterator>
 
template <typename T>
void bubble(T list1[], T list2[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list1[j] < list1[i]) {
        std::swap(list1[i], list1[j]);
        std::swap(list2[i], list2[j]);
      }
    }
  }
}
 
int main()
{
  int a[] = {9,8,7,6,5,4,3,2,1,0};
  int b[] = {6,7,5,8,9,0,4,3,2,1};
 
  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
 
  bubble(a, b, 10);
 
  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
}
#include <algorithm>
#include <iostream>
#include <iterator>

template <typename T>
void bubble(T list1[], T list2[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list1[j] < list1[i]) {
        std::swap(list1[i], list1[j]);
        std::swap(list2[i], list2[j]);
      }
    }
  }
}

int main()
{
  int a[] = {9,8,7,6,5,4,3,2,1,0};
  int b[] = {6,7,5,8,9,0,4,3,2,1};

  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';

  bubble(a, b, 10);

  copy(a, a + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
  copy(b, b + 10, std::ostream_iterator<int>(std::cout, " "));
  std::cout << '\n';
}

Or you can lump everything into a record structure and avoid that hassle and keep everything together automatically:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <algorithm>
#include <iostream>
#include <iterator>
 
struct record {
  int a;
  int b;
};
 
void bubble(record list[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list[j].a < list[i].a)
        std::swap(list[i], list[j]);
    }
  }
}
 
int main()
{
  record list[10] = {
    9,6,8,7,7,5,6,8,5,9,4,0,3,4,2,3,1,2,0,1
  };
 
  for (int i = 0; i < 10; i++)
    std::cout << '(' << list[i].a << ',' << list[i].b << ')' << '\n';
 
  std::cout << '\n';
  bubble(list, 10);
 
  for (int i = 0; i < 10; i++)
    std::cout << '(' << list[i].a << ',' << list[i].b << ')' << '\n';
}
#include <algorithm>
#include <iostream>
#include <iterator>

struct record {
  int a;
  int b;
};

void bubble(record list[], int sz)
{
  for (int i = 0; i < sz; i++) {
    for (int j = i; j < sz; j++) {
      if (list[j].a < list[i].a)
        std::swap(list[i], list[j]);
    }
  }
}

int main()
{
  record list[10] = {
    9,6,8,7,7,5,6,8,5,9,4,0,3,4,2,3,1,2,0,1
  };

  for (int i = 0; i < 10; i++)
    std::cout << '(' << list[i].a << ',' << list[i].b << ')' << '\n';

  std::cout << '\n';
  bubble(list, 10);

  for (int i = 0; i < 10; i++)
    std::cout << '(' << list[i].a << ',' << list[i].b << ')' << '\n';
}