Ad:

C Discussion Thread
Unsolved
Views: 2858

Jul 9th, 2008

Sorting an array of doubles?

Expand Post »

Hi.

The objective is to sort an array of doubles. My effort is listed below:

C Syntax (Toggle Plain Text)
#include <stdio.h>
#define MAX 10
 
void sort( double* n[], int q );
void print_nums( double* n[], int q );
 
int main( void ) {
 
   double* nums[MAX];
   int i; 
 
   for( i = 0; i < MAX; i++ ) {
      printf( "Please enter a double variable: " );
      scanf( "%f", &nums[i] );
   }
 
   sort( nums, 10 );
   print_nums( nums, 10 ); 
 
   return 0;
}
 
void sort( double* n[], int q ) {
 
   int a, b;
 
   double* x;
 
   for( a = 1; a < q; a++ ) {
      for( b = 0; b < q - 1; b++ ) {
         if( n[b] > n[b + 1] ) {
            x = n[ b ];
            n[b] = n[b + 1];
            n[b + 1] = x;
         }
      }
   }
}
 
void print_nums( double* n[], int q ) {
 
   int count;
 
   for( count = 0; count < q; count++ )
      printf( "\n%f", n[count] );
}
#include <stdio.h>
#define MAX 10

void sort( double* n[], int q );
void print_nums( double* n[], int q );

int main( void ) {

   double* nums[MAX];
   int i; 

   for( i = 0; i < MAX; i++ ) {
      printf( "Please enter a double variable: " );
      scanf( "%f", &nums[i] );
   }

   sort( nums, 10 );
   print_nums( nums, 10 ); 

   return 0;
}

void sort( double* n[], int q ) {

   int a, b;

   double* x;

   for( a = 1; a < q; a++ ) {
      for( b = 0; b < q - 1; b++ ) {
         if( n[b] > n[b + 1] ) {
            x = n[ b ];
            n[b] = n[b + 1];
            n[b + 1] = x;
         }
      }
   }
}

void print_nums( double* n[], int q ) {

   int count;

   for( count = 0; count < q; count++ )
      printf( "\n%f", n[count] );
}

The output I'm seeing is as follows:

C Syntax (Toggle Plain Text)
Please enter a double variable: 2.2
Please enter a double variable: 2.2
Please enter a double variable: 2.1
Please enter a double variable: 2.12
Please enter a double variable: 333.2
Please enter a double variable: 332.22
Please enter a double variable: 1.1
Please enter a double variable: 2.21
Please enter a double variable: 2.122
Please enter a double variable: 2.122
 
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
Please enter a double variable: 2.2
Please enter a double variable: 2.2
Please enter a double variable: 2.1
Please enter a double variable: 2.12
Please enter a double variable: 333.2
Please enter a double variable: 332.22
Please enter a double variable: 1.1
Please enter a double variable: 2.21
Please enter a double variable: 2.122
Please enter a double variable: 2.122

2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000
2.800000

Thanks,

Molly

Similar Threads

java_girl

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

6 posts
since Jul 2008

Permalink

Jul 9th, 2008

Re: Sorting an array of doubles?

Use %lf with scanf for type double .

[edit]But there are a number of indirection issues as well...

Last edited by Dave Sinkula; Jul 9th, 2008 at 10:14 pm.

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Jul 9th, 2008

Re: Sorting an array of doubles?

You have too much indirection.

(Toggle Plain Text)

#include <stdio.h>
#define MAX 10

void sort( double* n, int q );
void print_nums( double* n, int q );

int main( void ) {

   double nums[MAX];
   int i;

   for( i = 0; i < MAX; i++ ) {
      printf( "Please enter a double variable: " );
      scanf( "%lf", &nums[i] );
   }

   sort( nums, 10 );
   print_nums( nums, 10 );

   return 0;
}

void sort( double* n, int q ) {

   int a, b;

   double x;

   for( a = 1; a < q; a++ ) {
      for( b = 0; b < q - 1; b++ ) {
         if( n[b] > n[b + 1] ) {
            x = n[ b ];
            n[b] = n[b + 1];
            n[b + 1] = x;
         }
      }
   }
}

void print_nums( double* n, int q ) {

   int count;

   for( count = 0; count < q; count++ )
      printf( "\n%f", n[count] );
}

Last edited by Dave Sinkula; Jul 9th, 2008 at 10:22 pm.

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Jul 10th, 2008

Re: Sorting an array of doubles?

Thanks for the help Dave.

Looking at the initial exercise, it reads:

Write a program that uses pointers to type double variables to accept 10 numbers from the user, sort them, and print them to the screen.

C Syntax (Toggle Plain Text)
double* n[]
double* n[]

uses double indirection? If so, can you explain? I assumed it translated to:

'n' is an array (unspecified length) of pointers to type double.

Thanks,

Molly

java_girl

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

6 posts
since Jul 2008

Permalink

Jul 10th, 2008

Re: Sorting an array of doubles?

Click to Expand / Collapse Quote originally posted by java_girl ...

C Syntax (Toggle Plain Text)
double* n[]
double* n[]
uses double indirection? If so, can you explain? I assumed it translated to:

'n' is an array (unspecified length) of pointers to type double.

Not in a function prototype -- there it is a pointer to a pointer to double. You may want to peruse the earlier c-faq.com link again.

Dave Sinkula

Team Colleague

Reputation Points: 2780

Solved Threads: 312

long time no c

Offline

4,790 posts
since Apr 2004

Permalink

Jul 10th, 2008

Re: Sorting an array of doubles?

Quote ...

Write a program that uses pointers to type double variables to accept 10 numbers from the user, sort them, and print them to the screen.

This is pretty tricky. The question says "pointers to type double variable", but it don't anywhere say "pointers to type double array. Which is what is this

C Syntax (Toggle Plain Text)
double *n[];
double *n[];

That is totally wrong. That a pointer to a pointer. Well let me give you an example. With the above notation what you could do is this

C Syntax (Toggle Plain Text)
double arr1[] = { 20.5, 3.6, 452.3, 6.2, 4.25 };
double arr2[] = { 40.5, 3.5, 42.3, 6.2006, 45.25 };
 
double *array[10];
 
array[0] = arr1;
array[1] = arr2;
.
.
double arr1[] = { 20.5, 3.6, 452.3, 6.2, 4.25 };
double arr2[] = { 40.5, 3.5, 42.3, 6.2006, 45.25 };
       
double *array[10];

array[0] = arr1;
array[1] = arr2;
.
.

As you can the each elements of array hold an starting address of an array of doubles. If you are trying to sort that sort of an array its completely a different approach. You got to do more than what sort methods you have followed. You should consult your professor to make sure what he is expecting.

Well, at least i understand that from the question. Please correct if am wrong.

ssharish.

Last edited by ssharish2005; Jul 10th, 2008 at 12:51 pm.

ssharish2005

Reputation Points: 73

Solved Threads: 20

Posting Whiz in Training

Offline

253 posts
since Dec 2006

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C Forum Timeline: help me with this code

Next Thread in C Forum Timeline: How to understand this input/output code?

DaniWeb Message

Cancel Changes

User Name
Password