• C

Filling an array from a file of strings and search recursively within the array

I need to read an unknown number of strings out of a file (names) storing them in an array of size 20.  The file may have les than or more than 20 names in the file.  The array is then sorted in ascending ASCII order using a selection sort, printed and search for the position of a name until the user enters "quit".  I have written the program with two exceptions:

1.  Building the array from the file using fscanf.
2.  Ending the binary search by entering quit.  The user is continusously prompted...I cannot get the function to quit.

Here is the program:

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

#define NUMWORDS 20
#define LENWORDS 25

//Prototypes
void displayName (void);
void selection (char words [][]);
void printWords (char words [][]);
void getInput (char words [][]);
int search (int start, int end, char words [][], const char s[]);

//Main controls the

int main (int argc, char *argv[])
{
   FILE *infptr;
   char words [NUMWORDS][LENWORDS];
//{"love","mary","had","a","little","lamb","its","fleece","was","white","as","snow","ittzy","bittzy","spider","came","down","the","water","spout"};
   
   if (argc <= 1)
   {
     printf("\nNot enough command line arguments.\n");
   }
   infptr = fopen (argv [1], "r");
   if ((infptr)==NULL)
   {
      printf("\nERROR: Unable to open data for reading.\n\n");
   }
   if ((argc>=2) && ((infptr)!=NULL))
   {
      int i;
      for (i=0; i < NUMWORDS; i++)
        words [i] = fscanf (infptr, "%s", words[]);
      displayName ();
      selection (words);
      printWords (words);
      getInput (words);
   }
   //Format and finish.
   printf ("\n");
   return 0;
}

//The name of the programmer is displayed.
void displayName (void)
{
   printf("\nName: Chandra Parr\n\n");
}

void selection (char words [][LENWORDS])
{
   int i,j,k;
   int currMin=0;
   char temp[NUMWORDS];

   for (j=0; j < 19; j++)
   {
      currMin=j;
      for (k=j+1; k < 20; k++)
         if (strcmp(words[currMin], words[k])>0)
            currMin=k;
         strcpy(temp, words[currMin]);
         strcpy(words[currMin], words [j]);
         strcpy(words[j],temp);
   }
}

void printWords (char words [][LENWORDS])
{
   int i;

   for (i=0; i < NUMWORDS; i++)
      printf ("\n%d: %s", i, words[i]);
   printf ("\n\n");
}

void getInput (char words [][LENWORDS])
{
   int result;
   int scanResult;
   char searchWord [LENWORDS];

      do
      {
         printf("Please enter a word to search (or quit to stop): ");
         scanResult = scanf ("%s", searchWord);
         if (scanResult == 1)
         {
            result = search (0, NUMWORDS - 1, words, searchWord);
            printf("The word \"%s\"", searchWord);
            if (result == -1)
               printf (" was not found.\n");
            else
               printf (" was found at position %d.\n", result);
         }
         }
         while (scanResult == 1);
}

int search (int start, int end, char words [][LENWORDS], const char s[])
{
   int middle, cmpRes;
   
   if (start > end)
      return (-1);
   else if (start == end)
      if (strcmp(words[start], s) == 0)
         return start;
      else
         return (-1);
   else
   {
      middle = (start + end) / 2;
      cmpRes = strcmp(words[middle],s);
      if (cmpRes == 0)
         return middle;
      else if (cmpRes > 0)
         return search(start, middle - 1, words, s);
      else
         return search (middle + 1, end, words, s);
   }
}
csunnypl2Asked:
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PaulCaswellCommented:
>>1.  Building the array from the file using fscanf.
Instead of:

     for (i=0; i < NUMWORDS; i++)
        words [i] = fscanf (infptr, "%s", words[]);

try:

     for (i=0; i < NUMWORDS; i++)
        if ( fscanf (infptr, "%s", words[i]) == NULL ) strcpy(words[i],"");

>>2.  Ending the binary search by entering quit.  The user is continusously prompted...I cannot get the function to quit.
Instead of:
         while (scanResult == 1);

try:

         while (scanResult == 1 && strcmp(searchWord,"quit") != 0);

Paul
0

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