Insertion Sort in C

Welcome to the Insertion Sort in C page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>

void insertion_sort(long *, int); // insertion sort function

size_t parse_list(const char *orig_list, long **arr)          // used for parsing the input in array arr
{
    char *list;
    char *token;
    size_t num_elements = 0;
    int i;
    int curr_index = 0;
    long temp_num;

    /* find the length of the array */
    for (i = 0; orig_list[i]; i++) {
        if (orig_list[i] == ',') {
            num_elements++;
        }
    }

    /* if there are no commas, invalid input */
    if (num_elements == 0) {
        *arr = NULL;
        return 0;
    }

    /* since there is one more element than commas */
    num_elements++;

    /* allocate memory for the array */
    *arr = malloc(num_elements * sizeof(long));

    /* store numbers in the array */
    list = strdup(orig_list);
    token = strtok(list, ",");
    while (token != NULL) {
        errno = 0;
        temp_num = strtol(token, NULL, 10);
        if (errno != 0) {
            *arr = NULL;
            return 0;
        }

        (*arr)[curr_index++] = temp_num;

        token = strtok(NULL, ",");
    }

    free(list);

    return num_elements;
}

/* print the elements of array */
void print_array(long *arr, size_t num_elems)               
{
    int i;

    for (i = 0; i < num_elems - 1; i++) {
        printf("%ld, ", arr[i]);
    }

    printf("%ld\n", arr[num_elems - 1]);
}

/* error message if input is not in desired format */
void error_message()
{
    fputs("Usage: please provide a list of at least two integers to sort in the format \"1, 2, 3, 4, 5\"\n", stderr);
}

int main(int argc, char **argv)
{
    long *arr;
    long num_elements;

    if (argc < 2) {
        error_message();
        return 1;
    }

    num_elements = parse_list(argv[1], &arr);
    if (num_elements == 0) {
        error_message();
        return 1;
    }

    insertion_sort(arr, num_elements);
    print_array(arr, num_elements);

    free(arr);
}

void insertion_sort(long * arr_sort, int n)
{
    int i, j;
    int tmp;

    /* insertion sort logic */
    for(i = 1; i < n; i++)
    {
        tmp = arr_sort[i];
        for(j = i; j > 0 && arr_sort[j-1] > tmp; j--)
            arr_sort[j] = arr_sort[j-1];
        arr_sort[j] = tmp;
    }
}

Insertion Sort in C was written by:

• sourabbr

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.