/************************************************************************
*
* Purpose: To read numbers entered by the user and sort them.
* Author: M.J.Leslie
* Date: 30-Nov-94
*
************************************************************************/
/********** Preprocessor ***********************************************/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
/********** Functions ***************************************************/
int read_nums(int *);
void display_nums(int *);
int comp_nums(const int *, const int *);
/********** main ********************************************************/
main()
{
int numbers[30]; /* Numbers to be sorted. */
int how_many=0; /* Number of numbers entered */
/* Get the numbers */
how_many = read_nums(numbers);
puts("\nThese are the unsorted numbers\n");
display_nums(numbers);
/* SORT the numbers held in
* 'numbers'. */
qsort(
numbers, /* Pointer to elements */
how_many, /* Number of elements */
sizeof(int), /* size of one element. */
(void *)comp_nums /* Pointer to comparison function */
);
puts("\nThese are the sorted numbers\n");
display_nums(numbers);
}
/************************************************************************
*
* comp_nums: Compare two numbers.
*
************************************************************************/
int comp_nums(const int *num1, const int *num2)
{
if (*num1 < *num2) return -1;
if (*num1 == *num2) return 0;
if (*num1 > *num2) return 1;
}
/************************************************************************
*
* readnums: read numbers from the keyboard and put them into an array.
*
************************************************************************/
int read_nums(int *array)
{
char data[80]; /* Data entered by the user */
int inc=0;
puts("\n\tPlease enter some integer numbers");
puts("\tno checking is made on the data you enter....");
printf("\t==> ");
gets(data);
/* Assume we have valid data.
* Put it into an array. */
*(array+inc) = atoi(strtok(data," "));
inc++;
while ( *(array+inc) = atoi(strtok(NULL," "))) inc++;
/* Return the number of items
* stored in 'array'. */
return inc++;
}
/************************************************************************
*
* display_nums: Display the numbers
*
************************************************************************/
void display_nums(int *array)
{
/* NULL is a pointer to 0,
* so it must be cast to an
* integer */
while ( *array != (int)NULL)
{
printf("%d ",*array);
array++;
}
puts("");
}
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