C binary files vs. ascii files

Question

So im brand new to C. I need to write a program that takes in a binary file of integers as input, allocate a big enough array with malloc, then use the read() c function to store each integer in the binary file in its respective location in the array. My issue is that I don't know how to differentiate between the two. when I print out the data stored in this allocated array space it just shows the Ascii value of the binary data taken as a string of chars. so for example if I have the binary number 0000 0001, the array from locations [0]-[7] would be each ascii value of each bit in that binary number.

Basically im trying to read each line and store that lines int representation of the binary information in 1 array location, so like the above example the desired outcome would be: [0] - 1. Is there some conversion algorithm I need to do? I believe there to be a way for c to just recognize that its binary info, not ascii because there are 2 different file types: binary and ASCII. Any help would be greatly appreciated, thanks in advance!

P.s I can only use these function calls: open, close, read, malloc, fstat, printf

else
    {
            fileDescriptor = open(argv[1], O_RDONLY, 0);
            if (fileDescriptor == -1){
                    printf("File Not Found\n");
                    exit(1);
            }
            else{
                    if (fstat(fileDescriptor, &fileStat) < 0){
                            printf("Trouble pulling statistics of file\n");
                            exit(1);
                    }
                    else
                    {
                            numBytes = fileStat.st_size;
                            filePointer = (char*)  malloc(numBytes);
                    n = read(fileDescriptor, filePointer, (numBytes * sizeof(int)));

                            if( n < 0 ){
                                    printf("Problem reading the file\n");
                                    exit(1);
                            }
                                    numerator = 0;
                                    numCount = 0;
                                    average = 0;

                                    while(*filePointer != NULL)
                                    {
                                    numerator += *filePointer;
                                    printf("data in array: %d\n", *filePointer);
                                    filePointer++;
                                    numCount++;
                                    }
                            average = (double) numerator / (double) numCount;
                            printf("Average: %f\n", average);

                            printf("Total Numbers: %d\n", numCount);
                    }
            }

Answer 1

Your read() can go horribly wrong because you try to read numBytes integers but integers are not bytes. Should you have properly checked the return value from read, you would have seen as the file is not numBytes * sizeof(int) large. If the file indeed contains integers, and not strings of ASCII digits, then you can access the integers as:

int *pInt= (int *)filePointer;
while (pInt < filePointer+numBytes) { printf("%d,", *pInt); pInt++;}

If the file contains ASCII strings of digits, you need a separator to signal where one number ends and the next begins and can write:

char *s= filePointer;
while (s<filePointer+numBytes) {
    int num= 0;
    while (s<filePointer+numBytes && '0'<= *s && *s<='9') {
        num= num*10 + *s-'0';
        s++;
    }
    while (s<filePointer+numBytes && !('0'<= *s && *s<='9')) s++; // skip separator(s)
}

Answer 2

If you are trying to get the each bit from the binary file( not an ASCII file ) and store it in an array, then you can use the below code to do that.

If you want to know more about the difference fo ASCII and Binary file read the post https://stackoverflow.com/a/28301127/3095460

ASCII File is also a binary file, except, the characters are encoded with ascii character set and each character take only one byte in memory. for example if you want to put an integer 10000 in a binary file it needs only 4 bytes( size of an int in binary), but a ascii file will need 5 bytes. so reading 10000 from an ascii file will have read 5 bytes to get 10000 and decode to an integer, but a binary file just we have to read 4 bytes alone.

so to read a binary file, you need a binary file editor. otherwise normal editor will decode the binary file and show something we cannot understand with our naked eyes, until you look closely into the bytes.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

int main(){

    int fd;
    char out;
    struct stat fileStat;
    int* binArray;
    int bin_size = 0, i = 0, j = 0;

    if( (fd = open("binfile",O_RDONLY)) != -1) {
        if ( fstat(fd, &fileStat) == 0 ){
            if (fileStat.st_size != 0 &&
                ( binArray = (int*) malloc( fileStat.st_size * 8 )) != NULL) {
                for(i = 0; i < fileStat.st_size; ++i) {
                    if( read(fd, &out, sizeof(char)) == 1 ) {
                        for(j = 7; j >= 0; --j) {
                            binArray[bin_size++] = (out >> j) & 0x01;
                            printf("%d",binArray[bin_size-1]);
                        }
                    }
                }
            }
            else {
                fprintf(stderr,"Trouble Allocating Memory\n");
            }
        }
        else {
           fprintf(stderr,"Trouble pulling statistics of file\n");
        }
    }
    else {
       fprintf(stderr,"Trouble Opening the File\n");
    }
    close(fd);
}