Ok, Sort Problem...

Ok in my mind this worked lol. Will this not work, I know its kinda long, but I thought it would get the job done. Am I just not doing something right?

Code:

---


// This is the main project file for VC++ application project
// generated using an Application Wizard.

//#include <iomanip>
//#using <mscorlib.dll>
//#include <tchar.h>
//#include <stdlib.h>
//#include <conio.h>
//using namespace System;
//#include <stdlib.h>
//#include <cstring>
#include "stdafx.h"
#include <iostream>
#include <string>

using namespace std;

main()
{
        string strName;
        string strName2;
        string strName3;
        string strName4;
        string strName5;
        string strNameHold;
        string strAllNames = strName + strName2 + strName3 + strName4 + strName5;
   
    cout << "Alphabetical Order System \n\n\n";

        cout << "Enter Name # 1: ";
        cin >> strName;
        cout << "\n";

        cout << "Enter Name # 2: ";
        cin >> strName2;
        cout << "\n";
       
        cout << "Enter Name # 3: ";
        cin >> strName3;
        cout << "\n";
       
        cout << "Enter Name # 4: ";
        cin >> strName4;
        cout << "\n";
       
        cout << "Enter Name # 5: ";
        cin >> strName5;
        cout << "\n";

        //STRNAME IS GREATEST
        if (strName > strName2)
        {
strNameHold = strName;
strName = strName2;
strName2 = strNameHold;
        }

        if (strName > strName3)
        {
strNameHold = strName;
strName = strName3;
strName3 = strNameHold;
}

if (strName > strName4)
        {
strNameHold = strName;
strName = strName4;
strName4 = strNameHold;

if (strName > strName5)
        {
strNameHold = strName;
strName = strName5;
strName5 = strNameHold;

//STRNAME2 IS GREATEST

if (strName2 > strName)
        {
strNameHold = strName2;
strName2 = strName;
strName = strNameHold;

        }

if (strName2 > strName3)
        {
strNameHold = strName2;
strName2 = strName3;
strName3 = strNameHold;
        }

if (strName2 > strName4)
        {
strNameHold = strName2;
strName2 = strName4;
strName4 = strNameHold;
        }
if (strName2 > strName5)
        {
strNameHold = strName2;
strName2 = strName5;
strName5 = strNameHold;
        }
//STRNAME3 IS GREATEST

if (strName3 > strName)
        {
strNameHold = strName3;
strName3 = strName;
strName = strNameHold;

        }

if (strName3 > strName2)
        {
strNameHold = strName3;
strName3 = strName2;
strName2 = strNameHold;
        }

if (strName3 > strName4)
        {
strNameHold = strName3;
strName3 = strName4;
strName4 = strNameHold;
        }
if (strName3 > strName5)
        {
strNameHold = strName3;
strName3 = strName5;
strName5 = strNameHold;
        }
//STRNAME4 IS GREATEST

if (strName4 > strName)
        {
strNameHold = strName4;
strName4 = strName;
strName = strNameHold;

        }

if (strName4 > strName2)
        {
strNameHold = strName4;
strName4 = strName2;
strName2 = strNameHold;
        }

if (strName4 > strName3)
        {
strNameHold = strName4;
strName4 = strName3;
strName3 = strNameHold;
        }
if (strName4 > strName5)
        {
strNameHold = strName4;
strName4 = strName5;
strName5 = strNameHold;
        }
//STRNAME5 IS GREATEST

if (strName5 > strName)
        {
strNameHold = strName5;
strName5 = strName;
strName = strNameHold;

        }

if (strName5 > strName2)
        {
strNameHold = strName5;
strName5 = strName2;
strName2 = strNameHold;
        }

if (strName5 > strName3)
        {
strNameHold = strName5;
strName5 = strName3;
strName3 = strNameHold;
        }
if (strName5 > strName4)
        {
strNameHold = strName5;
strName5 = strName4;
strName4 = strNameHold;
        }       
        cout << strAllNames;
        //cout << "\n" << strName << "\n" << strName2 << "\n" << strName3 << "\n" << strName4 << "\n" << strName5;
        }
        return 0;
}
       

       
       
}

---

The compiler has absolutely no idea what you mean by string1 > string2. This would probably be a good method to use if you were sorting a series of numbers from least to greatest, but you're using strings - and the behavior of the > operator is not defined for strings. If you want to use this method you'll need to learn how to overload operators. Are you misunderstanding the method I decribed in your last thread?

What exactly is it that your trying to do?

Sean is right im confused why you are trying to compare strings with <> operators.....

well the thing is, that it worked fine with 1 if statement and it sorted it fine, its just when i added the others it got weird on me. *sigh*.

well even though they are strings, they still have a intger value right? So one would be greater or lesser than the other.....

Quote:

---

What exactly is it that your trying to do?

---

Oh my freakin' heck, son! He's trying to sort strings alphabetically! You actually posted several times in the thread that this originated from, you of all people on this board right now should know this! Please stop posting in threads you don't understand with, "what exactly is it that you're trying to do". Just because everyone had to ask that question in your threads does not mean you have license to do it in others, especially since you don't even understand how to include header files.

Quote:

---

well the thing is, that it worked fine with 1 if statement and it sorted it fine, its just when i added the others it got weird on me. *sigh*.

---

Oh - maybe the > operator is defined for strings - I forgot that you were using the C++ string class - the method I described is probably best suited for C-style string (simple arrays of char variables). I will leave this problem to someone who has more experience with the string class.

If the greater than / less than operators are indeed overloaded to handle strings in terms of alphabetical sorting, then I would guess the problem is just a mistake in your if statements. Your code certainly could be compacted and potentially made simpler by using an array of strings and a loop instead. If noone else can help you with this problem further, you might benefit from trying your algorithm on some numbers instead.

Technically strings do have an integer value. In C++, variables can be "casted" from one type to another, and one type that does this quite well is the char type, because it is simply a number that the compiler knows to interpret as a character (see also: ASCII numbers). The problem is that C++ strings are actually classes, which is where someone can define their own data type and make operators to work with that data type. A common example is people overloading the '+' operator to concatenate (add) strings.

So with that in mind, the < / > operators could really be defined for any number of purposes. The example I used earlier was string length, but you are referring to the string's value in terms of alphabetical sorting. What the operators actually were defined for, I'm not sure. I will look it up, but for the time being I still think someone more experienced with C++ Strings should be able to help you more.

Hmm off the top of my head:

Code:

---

#include <iostream>
#include <string>

using std::cout;
using std::cin;
using std::string;
const int numnames = 5;
int main()
{
  string names[numnames];
  for (int c=0; c < numnames; c++)
  {
    cout<<"Enter Name # "<<c<<": ";
    cin>>names[c];
  }
  // Sort using selection sort which is what you did the long way of
  for (int c1=0; c1 < numnames-1; c1++)
  {
    int min = c1;
    for (int c2=c1+1; c2 < numnames; c2++)
      if ( names[min] > names[c2] )
        min = c2;
    if ( c1 != min )
      names[c1].swap(names[min]);
  }
  for ( int c=0; c<numnames; c++)
    cout<<names[c]<<endl;
}

---

Note: I have not compiled this code so there may be a small mistake in there

Sean: there comparison operators are done using the compare() member function:
http://www.cppreference.com/cppstrin...s.html#compare

This might help in what you're trying to do. It's a similar problem.

Code:

---

#include <iostream>
#include <string>

using std::cout;
using std::cin;
using std::string;
const int numnames = 5;
int main()
{
  string names[numnames];
  for (int c=0; c < numnames; c++)
  {
    cout<<"Enter Name # "<<c<<": ";
    cin>>names[c];
  }
  // Sort using selection sort which is what you did the long way of
  for (int c1=0; c1 < numnames-1; c1++)
  {
    int min = c1;
    for (int c2=c1+1; c2 < numnames; c2++)
      if ( names[min] > names[c2] )
        min = c2;
    if ( c1 != min )
      names[c1].swap(names[min]);
  }
  for ( c=0; c<numnames; c++)
    cout<<names[c]<<endl;
}

---

I added some int declarations that Thantos forgot, and this reduces the number of errors. I do however still get the following two - I've never had these errors and can't figure out what they could be.

26 - Name lookup of 'c' changed for new ANSI 'for' scoping
11 - using obsolete binding at 'c'

At the very least, the code makes sense in one's mind and should help. This is why Thantos has an astronomically high reputation.

I tried the char, and I had a error the conversion between that and string.....I'm still messing with it. I've went over my if statements and I don't think I messed them up...but there are a good many of them, so I may have missed something.
You guys are really helpful though, and I appreciate your responses.

Quote:

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Sean: there comparison operators are done using the compare() member function:
http://www.cppreference.com/cppstri...ls.html#compare

---

Ahh - cool site. Thanks, man!

Ok I fixed my code. The error you were describing sean is because I had declared a variable called c in the first for loop and in the last for loop. Modern scoping rules limit it to the for loop but since I forgot the int in the last loop it had to change the to the old scoping rules such that its alive after you declare it till the end of the function.

I keep getting

fatal error C1010: unexpected end of file while looking for precompiled header directive

for the code Thantos provided....

any idea why?

Copy and paste the code you are compiling back here, it compiles just fine for me after I add using std::endl to the code.

nevermind fixed it...had to tell it which header alittle differently.

also if one you gets bored, you think you could comment his code?...
I've got some of it figured out, but arrays are greek to me....
I seem to learn better from commented code and messin with it, so if someone
doesn't mind. Thanks.

It might be easier to just add "using namespace std;" to your code instead of all these other using statements. It'll reference stuff that you won't need, but considering that this program is just being written so you can practice and learn, it's not a huge deal at all, and, that way you won't get errors everytime you add something new to your code.

thats what I ended up doing

I'll comment his code if you promise to go and read a tutorial on C++ arrays and loops.

ok ok lol...I'll read on them, suggestion on source? I have a c++ by example book....helps better in some areas than others.....

Code:

---

/*
  The next three lines simply include all
  the necessary packages
*/
#include <iostream>
#include <string>
using namespace std;

/*
  This declares a constant. Although the
  two words are completely opposite, think
  of a constant as a variable that never
  changes
*/
const int numnames = 5;

int main()
{
/*
  names is an array of strings, length is
  numnames, the constant value of 5
*/
  string names[numnames];
/*
  for (starting values;
      condition (if true, loop executes);
      what to increment variables by)
  {
      code to execute;
  }

  If you have multiple starting values,
  etc., you can separate them with commas.

  If you have just one line in the loop,
  you can omit the {}'s. Make sure you
  don't have a ; after the for statement.
*/
/*
  Reads in data to sort
*/
  for (int c=0; c < numnames; c++)
  {
    cout<<"Enter Name # "<<c<<": ";
    cin>>names[c];
  }
/*
  Main logic loop
  - Compares each string
  - Depending on results, will swap
  strings to eventually smooth
  everything into correct order
*/
  for (int c1=0; c1 < numnames-1; c1++)
  {
    int min = c1;
/*
  A nested loop - a loop inside a loop
*/
    for (int c2=c1+1; c2 < numnames; c2++)
      if ( names[min] > names[c2] )
        min = c2;
    if ( c1 != min )
      names[c1].swap(names[min]);
  }
/*
  This loop reads out the sorted strings
*/
  for ( c=0; c<numnames; c++)
    cout<<names[c]<<endl;
}

---

Just any half-decent tutorial from Google will do. If you have a book, use that.