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Я хочу изменить содержимое входного файла и отобразить обратное содержимое, но я не получаю его; я думаю, что допустил логическую ошибку.

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

int main() {
    char* c = malloc(10);
    char* c1 = malloc(10);
    char ch, arg1[100], arg2[100];
    int i, count = 0;
    FILE *fp, *fq;
    printf("Name of the file:");
    scanf("%s", arg1);
    fp = fopen(arg1, "w ");
    if (!fp) {
        perror("Failed to open file");
        return errno;
    }

    printf("ttt%snn", arg1);
    printf("ttInput the text into the filen");
    printf("ttPress Ctrl d to the stopn");
    while ((*c=getchar()) != EOF) {
        fwrite(c, 1, sizeof(c), fp);
        count  ;
    }

    printf("nn");
    fclose(fp);
    fp = fopen(arg1, "w ");
    printf("Name of the output file:");
    scanf("%s", arg2);
    printf("Reversing the contents of the file.......n");
    fq = fopen(arg2, "w ");
    printf("tt%snn", arg2);
    for (i = 1; i <= count; i  ) {
        fseek(fp, -(i   1), SEEK_END)
        fwrite(c1, 1, sizeof(c1), fq);
    }
    printf("Done....Opening the filen");
    rewind(fq);
    for (i = 0; i <= count; i  ) {
        ch = getc(fp);
        putc(ch, stdout);
    }
    fclose(fp);
    fclose(fq);
    return 0;
}
  

Вот пример программы, которая загружает файл в память, а затем печатает содержимое памяти в обратном порядке в стандартный вывод.

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

/* get the size of the file. No error checking here! */
long get_filesize(FILE *fp)
{
    long fsize;

    fseek(fp, 0, SEEK_END);
    fsize = ftell(fp);
    rewind(fp);

    return fsize;
}

int main(int argc, char *argv[])
{
    if(argv[1] == NULL) return EXIT_FAILURE;

    FILE *input;
    unsigned char *data;
    long filesize;
    int i;

    /* open target file */
    input = fopen(argv[1], "rb");
    if(input == NULL) exit(EXIT_FAILURE);

    /* retrieve size of the file */
    filesize = get_filesize(input); 
    if(filesize < 1) exit(EXIT_FAILURE);

    /* allocate space for the file */
    data = malloc(filesize * sizeof(unsigned char));
    if(data == NULL) exit(EXIT_FAILURE);

    /* read the file into buffer and close the file handle */
    fread(data, filesize, sizeof(unsigned char), input);
    fclose(input);

    /* print the file content from end to beginning */
    for(i = --filesize; i >= 0; --i)
        putchar(data[i]);

    /* free the data buffer memory */
    free(data);

    return EXIT_SUCCESS;
}
  

Ввод текста:

 Lorem Ipsum is simply dummy text of the printing and typesetting industry.
Lorem Ipsum has been the industry's standard dummy text ever since the 1500s,
when an unknown printer took a galley of type and scrambled it to make a type
specimen book.
  

Выводимый текст:

 .koob nemiceps epyt a ekam ot ti delbmarcs dna epyt fo yellag a koot retnirp
nwonknu na nehw ,s0051 eht ecnis reve txet ymmud dradnats s'yrtsudni eht neeb
sah muspI meroL .yrtsudni gnittesepyt dna gnitnirp eht fo txet ymmud ylpmis si
muspI meroL