Thread: reading from file and storing the values in an array!! HELP PLEASE!! :O

Hey everyone!

So i have a simple program that's supposed to read up to 50 values from a .txt file, store the values in an array, and print the values to the user. However, when I run the program, it just outputs nothing to the user..just a blank space, i don't see any values.... i created the .txt file and saved it into "My Documents" on my computer so I'm pretty sure the program knows how to access it....maybe there's another mistake in my code that i'm not catching?

If anyone would like to help, I would greatly appreciate your help!!
Thank You

And here's my code:

Code:

/*Written by: Kalpana Chinnappan
Date: January 17, 2013
Homework 1
*/
    #include <stdio.h>

    int main (void)
 {
    int nums[50];   //up to 50 element int array
    FILE *fp1;      //file pointer
    int i;

    //******************  code starts here ***************
    for(i=0;i<50;i++)   //initialize array with 0
        nums[i]=0;
    i=0;        //clean up and initialize LCV
    if ((fp1=fopen("votes.txt","r"))==NULL)
    {
    printf("votes.txt failed to open\n");
    return 1;
    }
    else
        while((fscanf(fp1,"%d",&nums[i]))!=EOF) //scanf and check EOF
        {
            printf("nums[%d] is %d\n",i,nums[i]);
            i++;
        }


    return 0;
 }

Other then the fact that:

Code:

    //******************  code starts here ***************
    for(i=0;i<50;i++)   //initialize array with 0
        nums[i]=0;

Can easily be done at initialization:

Code:

int nums[50] = {0};

There is nothing wrong with the code and as long as votes.txt is in the current directory the program is run from, should work fine. What are the contents of votes.txt?
Should be something like:

Code:

230 2398 34988 30489 9488 8598 34893 48984
34989 489 49848 58958 985

Like I said there is nothing in the code that is causing it to not work. How are you executing it? Is it just running a quick popup window and then disappears?

Regarding your logic, if each numerical value represents a candidate then why not do something like this:

Code:

#include <stdio.h>

int main(void)
{
    int candidates[5] = {0};
    int i;
    FILE * fp;

    /* note this has no 50 size limit as before.. */
    if (fp = fopen("votes.txt", "r")) {
        while (fscanf(fp, "%d", &i) != EOF) {
            /* invalid vote (out of range */
            if (i < 0 || i > 5) {
                fprintf(stderr, "Invalid Candidate: %d!\n", i);
                continue;
            }

            /* otherwise we got a valid vote, count it */
            ++candidates[i];
        }
        fclose(fp);
    }

    for (i = 0; i < 5; ++i) 
        printf("Candidate #%d had %d votes\n", i, candidates[i]);

    return 0;
}

Read and ANSWER my questions, then maybe you will figure it out ?

@nonpuz

Ok so you asked how I was executing it--I'm using codeblocks, just building and running the program. Ok, so I used the code you just gave me (the candidate one) and it's finally outputting some results!!! Thank you!! The only problem is that I need the up to 50 size limit to still be there (because what if I have more than 50 numbers?), but i'll try and figure that out on my own. Also, the output that i get is:

Candidate #0 had 0 votes
Candidate #1 had 0 votes
Candidate #2 had 0 votes
Candidate #3 had 0 votes
Candidate #4 had 0 votes
Candidate #5 had 0 votes
Candidate #6 had 0 votes
Candidate #7 had 0 votes
Candidate #8 had 0 votes
Candidate #9 had 0 votes

Process returned 0 (0x0) execution time : 0.031 s
Press any key to continue.

In my case, there are only 5 candidates, so ignore the output stuff for "candidate 5" to "candidate 9". Just look at the candidate vote count until "candidate 4". Somehow it says that all 5 candidates got 0 votes...how do I get the program to actually print out the number of votes each candidate has? please give me slight hints, I'll try to figure most of it out on my own, It wouldnt be fair if u did my homework for me haha :P

@Adak
Ohhhhh!! Wow cant imagine why I couldnt figure that out earlier haha! Thanks!!

Ok so that tells me that its not reading anything from your file. Either the file is not in the directory or it is not readable or fscanf is failing. Put a "printf()" call right after the "fopen" call that just says "openned file successfully". Execute and run and see if it outputs opened file successfully. If it does, then move on and put a printf() call in the while loop just before the ++candididate[i] line;