Thread: Need help opening file specified by user and referencing to it within function.

This program is intended to ask the user what file to open then use a function to process the data. I am having trouble figuring out how to use the pointers and addresses to accomplish this. Any ideas?

Code:

#include <stdio.h>
#include <math.h>

#define MAX_CONTESTANTS 9
#define MAX_JUDGES 100

// Set this to 1 if running DevC++, or 0 otherwise.
#define DEVCPP 1
#define DEBUG 0

void ucfidol(FILE* ifp);

int main() {
    //variable for file name
    char fileName[80];
    
    //ask for and read file name
    printf("What is the name of the input file with the UCF Idol data?\n");
    scanf("%s", fileName);
    
    FILE* ifp;
    ifp = fopen ("fileName", "r");
    ucfidol(ifp);
  
        system("PAUSE");
    return 0;
}
    
    /* 
Pre-condition: ifp points to the beginning of a file that stores data
               about UCF Idol shows, as specified in Program 4.
Post-condition: The results of all the shows in the file will be
                printed to the screen and FILE pointed to by ifp will
                be closed.
*/
void ucfidol(FILE* ifp){

    int numCases;
    int i,j,k;
    
    // Open the text file.
    //FILE* ifp
    //fin = fopen ("*ifp", "r");
    
    fscanf(ifp, "%d", &numCases);
    
    int bestContestant = 1;
    double bestScore = 0;
    
    // Go through each show.
    for (i=1; i<=numCases; i++) {
        
        // Read in the parameters for this show.
        int numContestants, numJudges, stdDevLimit;
        fscanf(ifp, "%d%d%d", &numContestants, &numJudges, &stdDevLimit);
        
        int allScores[MAX_CONTESTANTS][MAX_JUDGES];
        
        // Read in all the scores given in this show.
        for (j=0; j<numContestants; j++)
            for (k=0; k<numJudges; k++)
                fscanf(ifp, "%d", &allScores[j][k]);
        
        // Go through and calculate the average for each judge.
        double allAverages[MAX_JUDGES];
                
        for (j=0; j<numJudges; j++) {

            // Add up each score this judge gave.
            int sum = 0, score;
            for (k=0; k<numContestants; k++)
                sum += allScores[k][j];
                
            allAverages[j] = (double)sum/numContestants;
            
            if (DEBUG)
                printf("Judge %d avg = %lf\n", j+1, allAverages[j]);
        }
        
        // Now, go back and calculate the standard deviation of each judge.
        double allStdDev[MAX_JUDGES];

        for (j=0; j<numJudges; j++) {

            // Add up each term in the sum for the standard deviation.
            double sum = 0;;
            for (k=0; k<numContestants; k++)
                sum += pow(allAverages[j] - allScores[k][j], 2);
                
            // This is part of the formula. After this line, sum = variance.
            sum /= numContestants;
            
            // The square root of this is the standard deviation.
            allStdDev[j] = sqrt(sum);
            
        }
        
        // Calculate the number of cheating judges & store which ones are the
        // cheaters.
        int numCorruptJudges = 0;
        int badJudges[MAX_JUDGES];
        for (j=0; j<numJudges; j++) {   
            if (allStdDev[j] > stdDevLimit) {
                badJudges[numCorruptJudges] = j;
                numCorruptJudges++;
            }
        }
        
        // According to the rules, if all the judges are corrupt, none are.
        if (numCorruptJudges == numJudges)
            numCorruptJudges = 0;
            
        // Go through each contestant to find the best one.
        double bestScore = 0;
        int bestSinger = 0;
        for (j=0; j<numContestants; j++) {
            
            // Add up this contestant's VALID scores.
            double sum = 0;
            int judgeIndex = 0;
            for (k=0; k<numJudges; k++) {
            
                // These are the requirements of a corrupt judge.
                // This only works since the corrupt judges are stored in 
                // numerical order.
                if (judgeIndex < numCorruptJudges && badJudges[judgeIndex] == k) {
                    judgeIndex++;
                    continue;
                }
                
                sum += allScores[j][k];
            }
            
            
            // Based on the specs, this will never divide by 0.
            double avg = sum/(numJudges - numCorruptJudges);
            
            if (avg > bestScore) {
                bestScore = avg;    
                bestSinger = j;
            }        
        } // end j loop for all contestant scoring.
        
        // First part of the output, add one because contestant numbers are one based.
        printf("UCF IDOL SHOW #%d\n", i);
        printf("Contestant #%d, you win with an average score of %.2lf.\n", bestSinger+1, bestScore);
        
        // If all our judges behave.
        if (numCorruptJudges == 0)
            printf("All judges' scores were used.\n\n");
            
        // This is if we have some bad ones.
        else {
            printf("The following judges' scores were thrown out: ");
            
            for (j=0; j<numCorruptJudges; j++)
                printf("%d ", badJudges[j] + 1);    
            printf("\n\n");
        }
    } // End numCases loop.
    
    // Close the file.
    fclose(ifp);
}