The Shell Sort : Shell Sort « Search Sort « C Tutorial

1. C Tutorial
2. Search Sort
3. Shell Sort

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

  void shell(char *items, int count)
  {

    register int i, j, gap, k;
    char x, a[5];

    a[0]=9; a[1]=5; a[2]=3; a[3]=2; a[4]=1;

    for(k=0; k < 5; k++) {
      gap = a[k];
      for(i=gap; i < count; ++i) {
        x = items[i];
        for(j=i-gap; (x < items[j]) && (j >= 0); j=j-gap)
          items[j+gap] = items[j];
        items[j+gap] = x;
      }
    }
  }

  int main(void)
  {

    char s[255];

    printf("Enter a string:");
    gets(s);
    shell(s, strlen(s));
    printf("The sorted string is: %s.\n", s);

    return 0;
  }

Enter a string:3
The sorted string is: 3.