Character's frequency

#include < stdio.h >

#include<conio.h>
#include < string.h >

int main()
{
  char string[100];
  int c = 0, count[26] = {0};

  printf("Enter a string\n");
  gets(string);

  while ( string[c] != '\0' )
  {
  /* Considering characters from 'a' to 'z' only */

  if ( string[c] >= 'a' && string[c]   count[string[c]-'a']++;

  c++;
  }

  for ( c = 0 ; c < 26 ; c++ )
  {
  if( count[c] != 0 )
  printf("%c occurs %d times in the entered string.\n",c+'a',count[c]);
  }

getch();

}