Sorting a linked list alphabetical.

[micuklein]

Hi. Te problem asks for me to read 10 names from a file, put them in a single linked list and sort them. This is what I've done so far.......is it ok?
Cheers!

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

struct list1
{ string s;
list1 *next;
}
typedef list1 *list;

int main()
{
string file;
list *first, *last, *p;
first = last = new list;
list *prev = new list;


cout<<"Input the file name from where you want to read:";
cin>>file;


ifstream fin;
fin.open(file.c_str());
getline(fin,s);
fin>>first->s;
first->next=NULL;

while(!fin.eof())
{ last->next=new list;
last=last->next;
getline(fin,s);
fin>>last->s;
last->next=NULL;
}

for (list *i = first; i != NULL; i = i->next) {
cout << i->s << " ";
}

cout << endl;

bool ok = false;

while (!ok) {
ok = true;
prev->next = first;

for (list *i = first; i != last; i = i->next) {
if (i->s.compare(i->next->s) > 0) {
prev->next = i->next;
i->next = i->next->next;
prev->next->next = i;

ok = false;
}

prev = prev->next;
}

}

cout << "Sorted List: \n";

for (list *i = first; i != NULL; i = i->next) {
cout << i->s << " ";
}

cout << endl;

return 0;
}

[Adijunn]

So let me get this straight, you want to print a list of names in alphabetical order?

[micuklein]

Yes.
I read some name from a file. Put them in a list and then want to sort them. I think the sorting alg is wrong.

[Adijunn]

Yes I do have a sorting program that sorts integers from least to greatest, and you can just change all the ints to strings in order to make it into alphabetical order for words. I will send you this program when I get home and you could take a look at the algorithm I used.

[micuklein]

Cheers!

[Adijunn]

#include <iostream>

using namespace std;

void spot(int& a, int& b)
{
int temp;
temp = a;
a = b;
b = temp;
}

int main(int argc, const char * argv[])
{

int a[5];
for(int i=0; i<5; i++)
{
cin>>a[i];

}


int s = 0;

do {
s=0;
for(int x=0; x<4; x++)
{
if(a[x]>a[x+1])
{
spot(a[x], a[x+1]);
s++;
}
}

}while(s!=0);

cout<<"\n";

for(int b=0; b<5; b++)
{
cout<<a[b]<<"\n";
}

return 0;
}

[Adijunn]

This program sorts numbers in an array from least to greatest. If you want to read the names from a file and put them into a dynamic array, you have to use the fstream library, and for the dynamic array you need to use pointer references which you can look up.

[Adijunn]

You actually might not need to use dynamic arrays.

[Adijunn]

To change the program from sorting numbers from least to greatest to strings from least to greatest, you have to change the ints to strings.