Help with searching text file

Hi all, I've gotten very close with my project and just need a fresh pair of eyes to point out the obvious. My code seems to parse through the text file, yet does not actually search correctly. My search term of 'the' gave back 0 results, even though that word is obviously in there.

Code:

---

/*
 ask the user for a word
 convert user word to LOWER CASE
 open output file
 open input file
 test to be sure input file is open
 search for target word and keep count --> how??
 print results to monitor
 write results to file
 close files
 */
#include<stdio.h>
#include<stdlib.h>

int main (void)
{
        //declare
        int i =0;
        int count = 0;
       
        /*************************************************************
        working with arrays and strings
        *************************************************************/
        char mystring[50]; //what user puts in
        char target[50]; //the word in the file we are looking for
       
        printf("input your message ");
        scanf("%s", mystring);
        //printf("%s", mystring);
       
       
        /*************************************************************
        find file, write to it, output the string, end and close file
        **************************************************************/
       
        //define text file to use
        FILE * cfile;       
        //name of file == file
        cfile = fopen("./thanksgiving_proclamation.txt", "a+");
       
        //error handling if file does not exist
        if(cfile == NULL) printf("Cannot open file");
       
        /*************************************************************
                parse through file and search for string
        **************************************************************/       
        //convert string to lowercase
        for(i = 0; i < /*strlen(mystring)*/ 500; i++)//convert to string length
        {
                if(target[i] >= 'A' && target[i] <='Z')
                        //convert char between a and z into lowercase
                        target[i] = target[i] + 32; //makes uppercase char
        }
       
        //compare our strings
        do{
                //scan through file
                fscanf(cfile, "%s", mystring);       
               
                //convert string to lowercase
                for(i = 0; i < /*strlen(mystring)*/ 300; i++)//convert to string length
                {
                        if(mystring[i] >= 'A' && mystring[i] <='Z')
                                //convert char between a and z into lowercase
                                mystring[i] = mystring[i] + 32; //makes uppercase char
                }
                if(strcmp(mystring, target) == 0)
                        count++;
        }while(!feof(cfile));
       
        //while(strcmp(target,"quit")!=0)//end loop
       
         
        //print to file
        fprintf(cfile, "\nYour search '%s' was found %d times\n", mystring, count);
         
        //close file
        fclose(cfile);
       
        //show user file has been written
        printf("\nSuccess. File has been written\n");
       
        printf("Your search '%s' was found %d times \n", mystring, count);
       
        printf("Press Enter to Continue...");
        getchar();
        return 0;
}

---

Look at the string right in this part of the code:

Code:

---

        //compare our strings
        do{
                //scan through file
                fscanf(cfile, "%s", mystring);       
               
                //convert string to lowercase
                for(i = 0; i < /*strlen(mystring)*/ 300; i++)//convert to string length
                {
                        if(mystring[i] >= 'A' && mystring[i] <='Z')
                                //convert char between a and z into lowercase
                                mystring[i] = mystring[i] + 32; //makes uppercase char
                }

                printf("\n mystring: %s \n  target:%s mystring, target);
                //note particularly where the cursor is positioned after it prints the last word,
                //and any double spacing (vertically), which indicates a trailing newline is
                //attached to the end of the word. Usually it's a trailing newline or EOS char
                //difference in the words that goofs up the comparison.

                j = getchar(); //add int j to your variables

                if(strcmp(mystring, target) == 0)
                        count++;

---

Hmm. Here is what I added:

Code:

---

//compare our strings
        do{
                //scan through file
                fscanf(cfile, "%s", mystring);       
               
                //convert string to lowercase
                for(i = 0; i < /*strlen(mystring)*/ 300; i++)//convert to string length
                {
                        if(mystring[i] >= 'A' && mystring[i] <='Z')
                                //convert char between a and z into lowercase
                                mystring[i] = mystring[i] + 32; //makes uppercase char
                }
                printf("\n mystring: %s \n target:%s", mystring, target);
                int j;
                j = getchar(); //add int j to your variables
               
                if(strcmp(mystring, target) == 0)
                        count++;
        }while(!feof(cfile));

---

And here is what I'm seeing:

input your message the

mystring: the
target:
Success. File has been written
Your search 'the' was found 0 times
Press Enter to Continue...

Well I am not sure of your intent regarding the code for your target array. That seems to be pointless here. Also your are scaning your file for "mystring" then afterwards converting that to lower case?

When you actually compare mystring to target, what is target here, what it initialized to be?

Not sure, but is your intent to store the fscan function into target instead of mystring?


Also, not good practice to imbed /*comments */ within the statement. Please include comments at the head of the block/test/code piece.

My goal is to compare the user input (mystring) with the content of the text file (target). If they match then I need to keep a record (using my count variable) and print out how many times the user input (mystring) is seen in the text file.

I'm lost at the point of comparing :(

In a quick test, if you simply alter your code to use 'target' instead of mystring argument you should fare much better!

Quote:

---

Originally Posted by slingerland3g

In a quick test, if you simply alter your code to use 'target' instead of mystring argument you should fare much better!

---

Sorry, I am not exactly sure where I should switch mystring for target regarding your reply.

Good catch, Slingerland!

Zachary, you're bringing in the file words, and putting them into the wrong string.

Put them into the "target" string, instead.

Code:

---

//scan through file
                fscanf(cfile, "%s", mystring);        //change this to target


---

One more thing, there is some stack smashing happening as well, that I see. You may want to alter your loops to go as far as the string length, as you commented out. You will need to include string.h for this. Move your loop too alter your "target" string inside your 'do-while'.

Quote:

---

Originally Posted by slingerland3g

One more thing, there is some stack smashing happening as well, that I see. You may want to alter your loops to go as far as the string length, as you commented out. You will need to include string.h for this. Move your loop too alter your "target" string inside your 'do-while'.

---

Ah, the missing #include<string.h> is what was making the string length not work. Thanks for that :)

Also thanks Adak for pointing out the wrong string I'm looking for :) I really appreciate the help, as my eyes are bleeding from looking over this beast.

While I'm making progress I still can't get it to actually register with the textfile (target array) and match up my user input (mystring array). Below is revised code up to this point,

Code:

---

/*
 ask the user for a word
 convert user word to LOWER CASE
 open output file
 open input file
 test to be sure input file is open
 search for target word and keep count --> how??
 print results to monitor
 write results to file
 close files
 */
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main (void)
{
        //declare
        int i =0;
        int count = 0;
       
        /*************************************************************
        working with arrays and strings
        *************************************************************/
        char mystring[50]; //what user puts in
        char target[50]; //the word in the file we are looking for
       
        printf("input your message ");
        scanf("%s", mystring);
        //printf("%s", mystring);
       
       
        /*************************************************************
        find file, write to it, output the string, end and close file
        **************************************************************/
       
        //define text file to use
        FILE * cfile;       
        //name of file == file
        cfile = fopen("./thanksgiving_proclamation.txt", "a+");
       
        //error handling if file does not exist
        if(cfile == NULL) printf("Cannot open file");
       
        /*************************************************************
                parse through file and search for string
        **************************************************************/       
        //convert string to lowercase
        for(i = 0; i < strlen(mystring); i++)//convert to string length
        {
                if(target[i] >= 'A' && target[i] <='Z')
                        //convert char between a and z into lowercase
                        target[i] = target[i] + 32; //makes uppercase char
        }
       
        //compare our strings
        do{
                //scan through file
                fscanf(cfile, "%s", target);       
               
                //convert string to lowercase
                for(i = 0; i < strlen(mystring); i++)//convert to string length
                {
                        if(mystring[i] >= 'A' && mystring[i] <='Z')
                                //convert char between a and z into lowercase
                                mystring[i] = mystring[i] + 32; //makes uppercase char
                }
                /**********
                code help by adak on cboard
                **********/
               
                printf("\n mystring: %s \n target:%s", mystring, target);
                int j;
                j = getchar(); //add int j to your variables
               
                /*********
                end code help
                **********/
                if(strcmp(mystring, target) == 0)
                        count++;
        }while(!feof(cfile));
       
        //while(strcmp(target,"quit")!=0)//end loop
       
         
        //print to file
        fprintf(cfile, "\nYour search '%s' was found %d times\n", mystring, count);
         
        //close file
        fclose(cfile);
       
        //show user file has been written
        printf("\nSuccess. File has been written\n");
       
        printf("Your search '%s' was found %d times \n", mystring, count);
       
        printf("Press Enter to Continue...");
        getchar();
        return 0;
}

---

Would the issue of not comparing be in this part?

Code:

---

if(strcmp(mystring, target) == 0)
                        count++;

---

Quote:

---

while(!feof(cfile)

---

do not use feof to control loop - read FAQ

Why are you opening the text file, in append+ mode?

Aren't you just reading the file, from first word to last word?

This is what I think you were setting out to do with your program.

Code:

---

#include <stdio.h>
#include <string.h>  //strlen()
#include <ctype.h>  //isalpha()

int main (void)
{
        //declare
  FILE * cfile;       
  char ch;
  int len, j, i = 0;
  int count = 0;
       
  char target[20]; //the word we are looking for
  char mystring[20] = { '\0' }; //the word from the file

        /*************************************************************
        working with arrays and strings
        *************************************************************/

  printf("\n\n\n\n"); //clean some space

        /*************************************************************
        find file, write to it, output the string, end and close file
        **************************************************************/
       
        //define and open text file
  cfile = fopen("blessing.txt", "rt");
       
        //error handling if file does not exist
  if(cfile == NULL) printf("Cannot open file");
       
            // input target
  printf("Enter the target word I'm looking for: ");
  fgets(target, sizeof(target), stdin);
  printf("\nTarget: %s", target);
            //remove the newline fgets() adds, replace it with EOS char
  target[strlen(target) - 1] = '\0';
           
 
  for(i = 0; i < strlen(target); i++) //convert target to all lowercase
  {
    if(target[i] >= 'A' && target[i] <='Z')
        target[i] = target[i] + 32;
  }
  printf("\ntarget: %s", target);

        /*************************************************************
                parse through file and search for string
        **************************************************************/       
  i = 0; //prime the while "pump"

  while(1) {
    ch=fgetc(cfile); 
    if(ch == EOF)
      break;
    if(isalpha(ch)) {
      mystring[i] = ch;
      ++i;
    }
    else { //we should be at the end of the word
      //so set mystring's word, to all lowercase
      len = strlen(mystring);
      if(len == 0)
        continue;
      for(j = 0; j <= len; j++) {
        if(mystring[j] >= 'A' && mystring[j] <= 'Z')
          mystring[j] += ('a' - 'A');
      }
      //add the end of string char
      mystring[i+1] = '\0';
      //show nothing is going awry :)
      printf("\n mystring: %s", mystring);
      //see if the words are a match and count 'em up, if they are.
      if((strcmp(mystring, target)) == 0)
        count++;
     
      //remove the old word
      for(i = 0; i <= len; i++)
        mystring[i] = '\0';
     
      i = 0; //reset i for the next word
    }
  }
  //close file
  fclose(cfile);
       
  //show user file has been written 
  //printf("\nSuccess. File has been written\n");
       
  printf("\n\nYour search '%s' was found %d times \n", target, count);
       
  printf("Press Enter to Continue...");
  j = getchar();
  return 0;
}

---

I used this phrase, in the file "blessing.txt":
"For food, for raiment, for life and opportunity; for friendship and fellowship, we thank Thee, oh Lord."

It works properly, in limited testing.

At the bottom of the text file, I need to print what they searched for and how many times it showed up. This is why I was using a+. Is this not correct?

Quote:

---

Originally Posted by zacharyrs

At the bottom of the text file, I need to print what they searched for and how many times it showed up. This is why I was using a+. Is this not correct?

---

The file mode has nothing to do with printing out what the target was, or how many times it was found.

You should use "r" for read mode, when you want to search through a file from front to back. Append mode is for writing onto the end of the file (appending the new data).

Quote:

---

Originally Posted by Adak

The file mode has nothing to do with printing out what the target was, or how many times it was found.

You should use "r" for read mode, when you want to search through a file from front to back.

---

"r" will allow me to "read" and "write" to the file?

Quote:

---

Originally Posted by zacharyrs

"r" will allow me to "read" and "write" to the file?

---

No, only read.

Do you want to write something to a file, as well?

Quote:

---

Originally Posted by Adak

No, only read.

Do you want to write something to a file, as well?

---

Yeah I need to print - at the bottom of the text file - the mystring and target strings. that is why i was leaning towards the a+ cuz I thought it appended text at the end of the file?

Quote:

---

Originally Posted by Adak

Why are you opening the text file, in append+ mode?

Aren't you just reading the file, from first word to last word?

This is what I think you were setting out to do with your program.


I used this phrase, in the file "blessing.txt":
"For food, for raiment, for life and opportunity; for friendship and fellowship, we thank Thee, oh Lord."

It works properly, in limited testing.

---

Hmm. Looks like a lot of stuff I haven't learned yet in C :( At this point I'm just trying to get my program to work as it is... I really appreciate your help.

OK. You need to run the program I posted. The mystring words are printed up, one by one, as they are found, in the file.

The target is also printed up.

Neither action requires any data being written to a file.

I *tried* to just get your program to work, but it has some major major problems. After about 1/2 hour of that, I just removed a bunch of it, and pulled some of your code, into a new loop, with some new code.

Everything in there is as basic as I know how to make it. I could write up my own version of isalpha(), but why not use (and learn how to use), the functions in the standard C library?

Quote:

---

Originally Posted by Adak

OK. You need to run the program I posted. The mystring words are printed up, one by one, as they are found, in the file.

The target is also printed up.

Neither action requires any data being written to a file.

---

The problem is you are using code that we haven't been introduced to in class. It would make my prof asking questions, and I wouldn't even understand what I'm learning ;(

Is my code that crappy where it can't be fixed? I hope not :(

When you work with strings, you really have to do things step by step. You can't do things out of order, or overlook anything, because it's all sequentially handled. So if you make a mistake in step #3, everything past that will probably be garbage - not just the next step.

Quote:

---

Originally Posted by zacharyrs

The problem is you are using code that we haven't been introduced to in class. It would make my prof asking questions, and I wouldn't even understand what I'm learning ;(

Is my code that crappy where it can't be fixed? I hope not :(

---

It can be salvaged, but it will need some major re-arranging.

Try and look at my program (well, our program since I did steal some of your code, too). :p

Follow what it's doing:

1) get everything declared
2) open the file with the words
3) get the target string
4) set all letters in the target to lowercase
5) decide on how you want to loop through the file, and on how you want to handle the words from the file.

Everything has to go step by step - no jumping around!

:)

Hmm your program should work as is - after you have moved your "convert string to lower case" for your target. Also you were using the strlen(mystring) for this instead of strlen(target).

Also using a+ argument for fopen, is not wrong, but is that your intent as you will keep appending your results to this file and your program will fscan that as well. The other issue was to move your "convert to lower" code for your target, and place that within your do-while loop. You were about 90% done here and mostly correct besides those two major issues. Please check this out:

Code:

---


 /*
 ask the user for a word
 convert user word to LOWER CASE
 open output file
 open input file
 test to be sure input file is open
 search for target word and keep count --> how??
 print results to monitor
 write results to file
 close files
 */
#include<stdio.h>
#include<stdlib.h>
#include <string.h>
int
main (void)
{
  //declare
  int i = 0;
  int count = 0;

        /*************************************************************
        working with arrays and strings
        *************************************************************/
  char mystring[50];            //what user puts in
  char target[50];              //the word in the file we are looking for

  printf ("input your message ");
  scanf ("%s", mystring);
  //printf("%s", mystring);


        /*************************************************************
        find file, write to it, output the string, end and close file
        **************************************************************/

  //define text file to use
  FILE *cfile;
  //name of file == file
  cfile = fopen ("./thanksgiving_proclamation.txt", "a+");

  //error handling if file does not exist
  if (cfile == NULL)
    printf ("Cannot open file");

        /*************************************************************
                parse through file and search for string
        **************************************************************/

  //compare our strings
  do
    {
      //scan through file
      fscanf (cfile, "%s", target);

  //convert string to lowercase
  for (i = 0; i < strlen(target); i++)  //convert to string length
    {
      if (target[i] >= 'A' && target[i] <= 'Z')
        //convert char between a and z into lowercase
        target[i] = target[i] + 32;    //makes uppercase char
    }

      //convert string to lowercase
      for (i = 0; i < strlen(mystring); i++)    //convert to string length
{
          if (mystring[i] >= 'A' && mystring[i] <= 'Z')
            //convert char between a and z into lowercase
            mystring[i] = mystring[i] + 32;    //makes uppercase char
        }
      if (strcmp (mystring, target) == 0)
        count++;
    }
  while (!feof (cfile));

  //while(strcmp(target,"quit")!=0)//end loop


  //print to file
  fprintf (cfile, "\nYour search '%s' was found %d times\n", mystring, count);

  //close file
  fclose (cfile);

  //show user file has been written
  printf ("\nSuccess. File has been written\n");

  printf ("Your search '%s' was found %d times \n", mystring, count);

  printf ("Press Enter to Continue...");
  getchar ();
  return 0;
}

---

Quote:

---

Originally Posted by slingerland3g

Hmm your program should work as is - after you have moved your "convert string to lower case" for your target. Also you were using the strlen(mystring) for this instead of strlen(target).

Also using a+ argument for fopen, is not wrong, but is that your intent as you will keep appending your results to this file and your program will fscan that as well. The other issue was to move your "convert to lower" code for your target, and place that within your do-while loop. You were about 90% done here and mostly correct besides those two major issues. Please check this out:

Code:

---


 /*
 ask the user for a word
 convert user word to LOWER CASE
 open output file
 open input file
 test to be sure input file is open
 search for target word and keep count --> how??
 print results to monitor
 write results to file
 close files
 */
#include<stdio.h>
#include<stdlib.h>
#include <string.h>
int
main (void)
{
  //declare
  int i = 0;
  int count = 0;

        /*************************************************************
        working with arrays and strings
        *************************************************************/
  char mystring[50];            //what user puts in
  char target[50];              //the word in the file we are looking for

  printf ("input your message ");
  scanf ("%s", mystring);
  //printf("%s", mystring);


        /*************************************************************
        find file, write to it, output the string, end and close file
        **************************************************************/

  //define text file to use
  FILE *cfile;
  //name of file == file
  cfile = fopen ("./thanksgiving_proclamation.txt", "a+");

  //error handling if file does not exist
  if (cfile == NULL)
    printf ("Cannot open file");

        /*************************************************************
                parse through file and search for string
        **************************************************************/

  //compare our strings
  do
    {
      //scan through file
      fscanf (cfile, "%s", target);

  //convert string to lowercase
  for (i = 0; i < strlen(target); i++)  //convert to string length
    {
      if (target[i] >= 'A' && target[i] <= 'Z')
        //convert char between a and z into lowercase
        target[i] = target[i] + 32;    //makes uppercase char
    }

      //convert string to lowercase
      for (i = 0; i < strlen(mystring); i++)    //convert to string length
{
          if (mystring[i] >= 'A' && mystring[i] <= 'Z')
            //convert char between a and z into lowercase
            mystring[i] = mystring[i] + 32;    //makes uppercase char
        }
      if (strcmp (mystring, target) == 0)
        count++;
    }
  while (!feof (cfile));

  //while(strcmp(target,"quit")!=0)//end loop


  //print to file
  fprintf (cfile, "\nYour search '%s' was found %d times\n", mystring, count);

  //close file
  fclose (cfile);

  //show user file has been written
  printf ("\nSuccess. File has been written\n");

  printf ("Your search '%s' was found %d times \n", mystring, count);

  printf ("Press Enter to Continue...");
  getchar ();
  return 0;
}

---

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Thank you. I appreciate your help. However, I have used the search term 'the' and it does not display the number of times it was in there. The count looks like it should be working so I'm not sure what I'm doing wrong.

Weird, but great news: I changed 'a+' to 'r+' and it now works perfect.

Thank you so much for your kind help. Now I'm going to go through and see what I can fix to make it better. If you have thoughts on how to make this better, so I can learn for future programming, that would be great :)

When you use the append file mode to open a file, the file pointer is positioned at the very end of the file.

Unless you're adding data to the end of a file, that's something you *don't* want, 99.9% of the time.

Quote:

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Originally Posted by Adak

When you use the append file mode to open a file, the file pointer is positioned at the very end of the file.

Unless you're adding data to the end of a file, that's something you *don't* want, 99.9% of the time.

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Ah! that makes perfect sense. Now it works perfectly with the 'r+'.

Quote:

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Originally Posted by zacharyrs

Weird, but great news: I changed 'a+' to 'r+' and it now works perfect.

Thank you so much for your kind help. Now I'm going to go through and see what I can fix to make it better. If you have thoughts on how to make this better, so I can learn for future programming, that would be great :)

---

Yes, that is true if you have not closed the file handle. You will have to re-read the file in again to start a fresh search through. It worked in my case, using a+, since I went through only one iteration then closed the file handle.

Quote:

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Originally Posted by slingerland3g

Yes, that is true if you have not closed the file handle. You will have to re-read the file in again to start a fresh search through. It worked in my case, using a+, since I went through only one iteration then closed the file handle.

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But multiple searches would require 'r+'?

Yes, I believe that is what Adak was trying to point out.