String I/O issues - need help

[thatzilla]

I am a novice with respect to C programming. This is my first semester in college that I've taken a C class. I apologize if my question is a bit rudimentary.

The program I'm working on is an assignment that reads a text file and compares a word bank of strings to text messages to check for misspelled words and such. The first line in the input file is n numbers of words in the "dictionary" (the proper words which are used for comparison). The next n lines are the words contained in the dictionary.

I'm having trouble reading these strings into a 2-dimensional array with n rows and 30 columns (the words cannot be more than 29 characters + 1 null character). Here's what I have:

int main() {
    FILE *textMsg; // Text input file pointer
    int n, m, t, w; // Asignment variables from in-text values
    int i, j, k; // Counter variables
    char c;

    if((textMsg = fopen("textmsg.txt", "r")) == NULL ){
        printf("Sorry, the file could not be opened.\n\n");
        system("PAUSE");
        return 0;
    }
    
    fscanf(textMsg, "%d", &n); // Get number of words in the dictionary

    char dictionary[n][30]; // Declares the array to store the dictionary words

    while(!feof(textMsg)){
        for(i = 0; i <= n; ++i){
            for(j = 0; j <= 30; ++j){
                fgets(*dictionary, j, textMsg);
            } 
        } 
    } 

    fclose(textMsg);

    system("PAUSE");

    return 0;
}

I have obviously included the string.h header. I was using the fgets() function to read each line until the new line character, hoping that it would only store that many characters and then move onto the next interation in the loop, but its reading the entire file, not n lines of text and <30 characters per line. The dictionary words are only a small chunk of the entire file so there will be multiple arrays in the final product which is why I'm not interested in reading the entire file.

[itCbitC]

methinks you don't need the inner for loop; store every word (<=29 chars) into each of the elements of dictionary[], as in:

for (i = 0; i < n; ++i)
    fgets(dictionary[i], sizeof dictionary[i], textMsg);

[thatzilla]

That still reads the entire file when I try to print the contents of dictionary[i].

[itCbitC]

Isn't each line of the input file a dictionary word <= 30 characters ??

[thatzilla]

Not necessarily. It's only supposed to read a maximum of 29 characters. And theres a lot of text in the input file, but I only want to read the first n lines for the dictionary array.

[itCbitC]

can you post a sample of the input file

[thatzilla]

This is an example that the professor made:

4
i
jason
love
you
2
ahole
jerk
5
4:21 AM
4 Jason I LOVE you
3:34 PM
4 Jason I love you
2:00 AM
4 Jsoan I lve you
4:00 AM
3 Jason you ahole
7:00 AM
3 Jason you jerk


4 is the number of dictionary words, 2 is the number of forbidden words, and 5 is the number of text messages that the program has to check for misspelled and swear words.

At this point, I get n which is 4 and then I only want to read the next 4 lines into the dictionary array.

[itCbitC]

At first I didn't notice that the two for loops were enclosed in a while loop.
In any case feof() is not a good test for the terminal condition, see this site's faq as to why.

while(!feof(textMsg)) {
        for(i = 0; i <= n; ++i){
            for(j = 0; j <= 30; ++j){
                fgets(*dictionary, j, textMsg);
            } 
        } 
}

Replace the entire code snippet above with the for loop below.

for (i = 0; i < n; ++i)
    fgets(dictionary[i], sizeof dictionary[i], textMsg);

[itCbitC]

Note that fscanf() stops when it sees the newline at the end of the first line so skip over it before calling fgets() otherwise the first string read will be NULL.

[thatzilla]

Can you explain that?

[itCbitC]

Change your fscanf() call so that there's trailing whitespace after the %d conversion spec.

fscanf(textMsg, "%d ", &n);

[thatzilla]

I did that and I still get 4 NULLs printed out.

[itCbitC]

I did that and I still get 4 NULLs printed out.

can you post your updated code!

[thatzilla]

Nevermind I got it! Thanks man!