Finding word in file

Suppose I have list in a text file formatted in such a way where the list is numbered 1A, 1B, 1C, 2A, 2B, ...:

Code:

*
*
*

7C
Guy
Fawkes

*
*
*

What would be the most efficient way to find and replace the first and last names with given values?

Here's my attempt:

Code:

int assign ()
{
	char ch, str[3];
	int j, number1, number2, redo = 0;

	while (redo == 0)
	{
        printf("\nInput seat number: ");
        scanf("%d", &number1);
        scanf("%c", &ch);
        getchar();

        if (number1 <= 30)
        {
            switch (ch)
            {
                case 'a':
                case 'A':
                number2 = number1; redo = 1; break;

                case 'b':
                case 'B':
                number2 = number1 + 10; redo = 1; break;

                case 'c':
                case 'C':
                number2 = number1 + 20; redo = 1; break;

                default:
                printf("Invalid seat number.\n");break;
            }
        }

        else
		printf("Invalid seat number.\n");
	}

    if (seat[number2].flag == 0)
    {
        printf("Insert first name: ");
        gets(seat[number2].fname);
        printf("Insert last name: ");
        gets(seat[number2].lname);
        sprintf(seat[number2].no, "%d%c", number1, ch);
        seat[number2].flag = 1;
        printf("\n");

        if (fgets(str, 3, f) == seat[number2].no)
        {
            fseek(f, +1L, SEEK_CUR);
            fputs(seat[number2].fname, f);
            fputc('\n', f);
            fputs(seat[number2].lname, f);
        }
    }

    else
    printf("This seat has already been assigned.\n");

    return 0;
}

The fgets part doesn't seem to work.

Originally Posted by 843

Suppose I have list in a text file formatted in such a way where the list is numbered 1A, 1B, 1C, 2A, 2B, ...:

Code:

*
*
*

7C
Guy Fawkes

*
*
*

What would be the most efficient way to find and extract the first and last names into variables?

You are talking about strings. Characters and words to strings. The problem with that is that you would be writing them to an Array meaning that the array would have to contain all of the same data types. If you are using data that is of different types then using a struct with pointers may be more beneficial.

Yeah, I'm using a struct. Sorry, just edited my post.

OK, you have a text file, and you want to replace Guy Fawkes with some other name.

How big is the text file? How many rows of text do you expect it to have, max?

30 seats, 10 rows and 3 columns. The file first lists the sequence from 1A to 10A, then 1B to 10B and finally 1C to 10C. Upon initialization, the names would simply be "Unassigned", but it will be replaced by names like "Guy Fawkes". While can be done in one line, I don't know how to parse a string, so I split it into two. Even if I know how to parse, I have to account for people with multiple last names or the likes, so I suppose this way is easier. Having two lines of "Unassigned" wouldn't make sense, and listing "First name: " beforehand complicates things a lot given my limited coding skills.

It looks like this:

Code:

1A
Unassigned

2A
Unassigned

3A
Unassigned

4A
Unassigned

5A
Unassigned

6A
Unassigned

7A
Unassigned

*
*
*

So an array of structs would be ideal. Each struct has a seat designation, and a name (or Unassigned), given to it.

Have you prototyped the struct above main() yet? That's a very convenient way to handle that.

Then you can read in your data into the array of structs, make your changes as needed, and write out the new data to a temp.txt file. Then close the files, remove the old file, and name the temp.txt file, into the original text file name.

I know this sounds insanely difficult, but it's way easy. Harder to describe it than to do it.

You can always change the data right inside the file, but then you run a bit more risk of goofing up the file.

It's already in an array of structs. My problem is not with data handling, but more of text manipulation in the file. I can post the full code (about 400 lines) here if you wish, but it's nowhere near complete yet.

Here's the structure identification:

Code:

struct info{
	char no[3];
	char fname[20];
	char lname[20];
        int flag;
	};

The flag is used to tell if the seat is assigned.

Text manipulation?

Please specify in detail.

I would like the program to search the file for a specific seat (which is user-defined), then replacing the "Unassigned" string into first and last names, which may or may not be split into two lines.

Another function would be reading the file and storing all those info into internal memory (the struct elements).

Finally, I need to find a way to flag the assignment on the external file. Perhaps if (fgets != "Unassigned") may work, but I haven't implemented it yet.

The code attempt is in my first post.

You need to make up your mind about the names - two lines is easiest, but either can work. Code to handle one line, won't work for two lines, however.

For this small amount of data a simple sequential search is fine:

Code:

/* be sure to take in the seat number, as a string, NOT as an integer */
for(i=0;i<SEATS;i++) {
  if(targetSeat==array[i].no) {
     //found the seat number
     strcpy(array[i].fname, newfName); 
     //handle last name as needed
  }
}

What has you stumped with reading in the data from the file?

You can use a simple format like:

Code:

fscanf(yourFilePointer, "%s%*c", array[i].no); //etc.

for each struct member. Again, you have to have the format of the names (one line or two), decided on, and adjust the code for that.

Ah, I'm an idiot to loop through the actual text file instead of the arrays. This should make things easier. Thanks for the help.

Could anyone please tell me what's wrong with this code? The output for 10A, 10B, and 10C is somehow missing its seat[10].fname string. I've narrowed the culprit down to the following code.

Code:

    for (i = 1; i <= 30; i++)
    {
        if (i <= 10)
        {sprintf(seat[i].no, "%dA", i);
        printf("%s%d", seat[10].fname, i); // the string still holds here
        printf("%s%d", seat[10].lname, i);}

        else if (i <= 20)
        sprintf(seat[i].no, "%dB", i - 10);

        else if (i <= 30)
        sprintf(seat[i].no, "%dC", i - 20);
    }

If I changed the code to

Code:

    for (i = 1; i <= 30; i++)
    {
        if (i <= 10)
        sprintf(seat[i].no, "%dA", i);

        else if (i <= 20)
        {sprintf(seat[i].no, "%dB", i - 10);
        printf("%s%d", seat[10].fname, i); //string disappears!
        printf("%s%d", seat[10].lname, i);}

        else if (i <= 30)
        sprintf(seat[i].no, "%dC", i - 20);
    }

EDIT: Got it! I forgot about '\0' in the declaration.