/*      Introduction to program:
        Program - inssort.c.
        Sorts a user-inputed list using the insertion sort algorithm.
        Francis O'Donovan 29-12-97. */

/*      Files to be #included. */

        #include <stdio.h>

/*      #definitions. */

        #define LENGTH 10       /* Number of elements in list. */

/*      Function: main() */

        void main()
        {
                /* Variable definitions. */

                        int i, j, k;                /* Counters. */
                        int key;                    /* key for Insertion sort algorithm. */
                        int A[ LENGTH];    /* List which user will fill with values. */

                /* Print introduction on screen. */

                        printf( "Program: inssort.c.\n\n" );
                        printf( "Sorts a user-inputed list using the insertion sort" );
                        printf( " algorithm.\n\n" );
                        printf( "Francis O'Donovan 29-12-97.\n\n" );

                /* Input list from user. */

                        printf( "Please type in the list of integers, pressing return " );
                        printf( "after each element.\n\n" );

                        for ( i = 0; i < LENGTH; i++ )
                        {
                                printf( "Element %d: ", i+1 );
                                scanf( "%d", &A[i] );
                        }

                /* Sort the list using the Insertion Sort algorithm. */

                        for ( j = 1; j < LENGTH; j++ )  /* Goes through list*/
                        {
                                key = A[j];             /* Set the new key to A[j]. */
                                k = j - 1;              /* Go through list from right. */

                                while ( ( k >= 0) && ( A[k] > key ) )
 
                                /* Do this until you reach the start of the list,
                                or you find the correct placement for key. */
 
                                {
                                        A[k+1] = A[k];
                                        /* Move kth element to (k+1)th position. */
                                        k--;
                                }

                                A[k+1] = key;
                                /* Put key in (k+1) position. */
                        }

                /* Print out list. */

                        for ( i = 0; i < LENGTH; i++)
                        {
                                printf( "%d ", A[i] );
                        }
        }

© Francis O'Donovan 1999.