Thread: scanning file and printing an array

hi, i am a new member here and first semester as a student using programming for my major (Geomatics Engineering). any feedback would be immensely appreciated. here it goes:
(also, pardon my probable terrible formatting, first post).

i am to write a program that reads a file that reads 3 arrays (essentially a 3x3 matrix) and i will end up printing them into a new file along with computing the averages of the values (column 1 avg,...)

however i am stuck far from that.

Code:

/*
* Programmer:        Jeff Clay
* Class:            GME 61
* Date:            8-7-12
* Program:            READING IN ARRAYS
*
* Purpose:            READ IN ARRAYS, COMPUTE AVERAGE
*
*/


#include <stdio.h>
#include <stdlib.h>
#define maxRow 2
#define maxCol 3
#define _CRT_SECURE_NO_WARNINGS




void printMatrix(double array[maxRow][maxCol], int row, int column);
void add_matrices(double xArray[maxRow][maxCol], double yArray[maxRow][maxCol], double zArray[maxRow][maxCol], int row, int column);


main()
{
    double xArray[1][3], yArray[1][3], zArray[1][3];
    char fileName[256];
    int i,j;
    FILE *fileIn, *fileOut;


    i=0;
    j=0;




    printf("Enter input file path:\n");
    gets(fileName);
    fileIn=fopen(fileName, "r");


    if (fileName==NULL)
    {
        printf("Filepath DNE");
        exit(-1);
    }


    /*printf("Enter output file path:\n");
    gets(fileName);
    fileOut=fopen(fileName, "w");


    if (fileName==NULL)
    {
        printf("Filepath DNE");
        exit(-1);
    }*/


    while(fscanf_s(fileIn,"%lf", &xArray[3][1])!=EOF)
        /*add_matrices(xArray,yArray,zArray,3,1);*/
    {
        printMatrix(xArray,3,1);
        /*printf("+ \n");*/
    }






    /*double a[2][3]={{1.0,  2.0,  3.5},{4.0,  5.0,  6.0}};
    double b[2][3]={{-6.0,  -5.0,  -4.0},{  -3.0,  -2.1,  -1.5}};
    double c[2][3];


    add_matrices(a,b,c,3,2);
    {
        printMatrix(a,3,2);
        printf("+ \n");
        printMatrix(b,3,2);
        printf("= \n");
        printMatrix(c,3,2);
    }*/
}
void printMatrix(double array[maxRow][maxCol], int row, int column)
{
    int i, j;
    for (i=0; i<column; i++)
        {
        for (j=0; j<row; j++)
            printf("%.2lf\t", array[i][j]);
            printf("\n");
        }
}

i'll be kind of honest, i am pretty lost on what i am doing and what to do. i understand the concept of an array, however the coding is not friendly to me.

thank you

Hey there - Welcome to the forum

A few things...

"main" should be declared as int and returning a value - If you want to use argv/argc, you will need to put them into main's parameters.


Never use gets(). It's a dangerous function which is not even in the new C standard.


You should be checking to see if fileIn is NULL, not fileName.


I'll stop there

> any feedback would be immensely appreciated.
...

> thank you for replying, however: ......

Sorry, but that just didn't sound like "immensely appreciated".

> i'll be kind of honest, i am pretty lost on what i am doing and what to do.
Maybe it's because your teacher doesn't know enough about C. The gets() thing is a real red flag marking out poor teachers.

> using programming for my major (Geomatics Engineering)
So is programming something you really want to learn, or just a hurdle to jump over, only to be forgotten as soon as you've got your passing grade for this module?

> i am to write a program that reads a file that reads 3 arrays (essentially a 3x3 matrix)
#define maxRow 2
#define maxCol 3
Why is maxRow not 3?

> double xArray[1][3], yArray[1][3], zArray[1][3];
Why are these not using your #define names?

> while(fscanf_s(fileIn,"%lf", &xArray[3][1])!=EOF)
This does NOT fill the whole array with numbers.
You need a loop to assign each array[row][col] individually.