c program to sort a string in alphabetic order

C program to sort a string in alphabetic order: For example if user will enter a string "programming" then output will be "aggimmnoprr" or output string will contain characters in alphabetical order.

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

main()

{

      char string[100], ch, *pointer, *result, *temp;

      int c, length;

       printf("Enter a string\n");

      gets(string);

      length = strlen(string);

       temp = result = (char*)malloc(length+1);

       pointer = string;

       for ( ch = 'a' ; ch <= 'z' ; ch++ )

      {

          for ( c = 0 ; c < length ; c++ )

          {

              if ( *pointer == ch )

              {

                 *result = *pointer;

                 result++;

              }

              pointer++;

          }

          pointer = string;

      }

      *result = '\0';

       result = temp;

       strcpy(string, result);

       free(result);      

       printf("%s\n", string);

       return 0;

}