my 'reverse' code works on wav files but it doesn't pass check50

Question

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include "wav.h"

int check_format(WAVHEADER header);
int get_block_size(WAVHEADER header);

int main(int argc, char *argv[])
{
    // Ensure proper usage
    // TODO #1 (done)
    if (argc != 3) // 3 arguments 1 for the run, 1 for input , 1 for output
    {
        printf("./reverse input.wav output.wav\n");
        return 1;
    }


    // Open input file for reading
    // TODO #2 (done)
    FILE *file; // creating a pointer to file
    file = fopen(argv[1], "r");//opening the file with "r" for read only

    if (file == NULL) // making sure the file is opened
    {
        return 1;
    }


    // Read header
    // TODO #3(done)
    WAVHEADER header; //creating a place to store the header
    WAVHEADER* header1 = &header; // creating a pointer for the sake of the function w/ size of the header
    fread(header1, sizeof(WAVHEADER), 1, file); //reading from the file into the header
    //(the file to read into, size of what we will read, n. of times, source)
    header = *header1; //putting the data we took in it's place


    // Use check_format to ensure WAV format
    // TODO #4(done)
    if(check_format(header) != 1)
    {
        return 1;
    }


    // Open output file for writing
    // TODO #5 (done)
    FILE* outfile;
    outfile = fopen(argv[2], "w"); //"w" for write
    if (outfile == NULL)
    {
        return 1;
        printf("output file failed to open \n");
    }


    // Write header to file
    // TODO #6 (done)
    fwrite(header1, sizeof(WAVHEADER), 1, outfile);
    //(the sorce, size, n. of times, the file to write in)


    // Use get_block_size to calculate size of block
    // TODO #7(done)
    int size = get_block_size(header);


    // Write reversed audio to file
    // TODO #8
    int pointerStart = ftell(file);
    fseek(file, 0, SEEK_END);
    fseek(outfile, pointerStart, SEEK_SET);
    int pointerEnd = ftell(file);
    char buffer[size];
    for (int i =0 ; i < pointerEnd ; i++)
    {
        fseek(file, -i, SEEK_END);
        fread(buffer, size,1, file);
        fseek(outfile, pointerStart +i, SEEK_SET);
        fwrite(buffer, size, 1, outfile);
    }

    //closing files
    fclose(file);
    fclose(outfile);
}

int check_format(WAVHEADER header)
{
    // TODO #4 (done)
    BYTE test[4] = "WAVE";
    for (int i = 0; i < 4; i++)
    {
        if (header.format[i] != test[i])
        {
            return 2;
        }
    }
    return 1;
}

int get_block_size(WAVHEADER header)
{
    // TODO #7 (done)
    int bsize;
    bsize = header.numChannels * (header.bitsPerSample/8);
    return bsize;
}

this is the whole code and i can't find what's wrong i tried changing the

for (int i =0 ; i < pointerEnd ; i++)
    {
        fseek(file, -i, SEEK_END);
        fread(buffer, size,1, file);
        fseek(outfile, pointerStart +i, SEEK_SET);
        fwrite(buffer, size, 1, outfile);
    }

to

for (int i =0 ; i < pointerEnd - pointerStart; i++)
    {
        fseek(file, -i, SEEK_END);
        fread(buffer, size,1, file);
        fseek(outfile, pointerStart +i, SEEK_SET);
        fwrite(buffer, size, 1, outfile);

because it made sense for a moment but it didn't work so i removed it

Answer 1

Fixed it

    int headsize = 44;
    int pointerStart = ftell(file);
    fseek(file, 0, SEEK_END);
    fseek(outfile, headsize, SEEK_SET);
    int pointerEnd = ftell(file);
    BYTE buffer[size];
    fseek(file, -1*size, SEEK_END);
    for (int i= (pointerEnd - pointerStart)/size ; i>0 ; i--)
    {
        fread(buffer, size,1, file);
        fwrite(buffer, size, 1, outfile);
        fseek(file, -2*size, SEEK_CUR);
    }

first i changed the buffer into BYTE instead of char since the data is in bytes and i set the size to size(block_size) to store one block then i set the file pointer to one block before the end of file to start with it then in the loop i set i to the number of blocks by getting the number of bytes and deviding it by the size of a single block and i started reading one block into the buffer then writing it into the outfile then i made the pointer of the file move two blocks back, one for the block it just copied and one for the next block since it moves when it reades anything