include stdio include stdlib include conio include windows include io

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <windows.h>
#include <io.h>
#include <locale>
#define FNAME "myfile.bin"

void Reverse(char *filename)
{
	FILE *f;
	int buff, buff2;
	bool canExit = false;
	fpos_t dbg, len;
	if (!(f = fopen(filename, "r+b")))
	{
        puts("error");
		return;
	}
	len=filelength(fileno(f));
	do
	{
		fread(&buff,sizeof(int),1,f);
		fseek(f,sizeof(int),SEEK_CUR);
		fread(&buff2,sizeof(int),1,f);
		fseek(f,-sizeof(int),SEEK_CUR);
		fwrite(&buff,sizeof(int),1,f);
		fgetpos(f,&dbg);
		if(dbg==len) canExit=true;
		fseek(f,3*(-sizeof(int)),SEEK_CUR);
		fwrite(&buff2,sizeof(int),1,f);
		fflush(f);
	} while(!canExit);
	fclose(f);
}

void printFile(char *filename)
{
	FILE *f;
	int buff;
	if (!(f = fopen(filename, "rb")))
	{
        puts("error");
		return;
	}
	do
	{
		fread(&buff,sizeof(int),1,f);
		if (!feof(f)) printf("%d",buff); else break;
	} while(!feof(f));
	puts("EOF");
	fclose(f);
}


void inputFile(char *filename)
{
	FILE *f;
	int buff;
	if (!(f = fopen(filename, "w+b")))
	{
        puts("error");
		return;
	}
	do
	{
		printf("Введите число: ");
		scanf("%d",&buff);
		fflush(stdin);
		fwrite(&buff,sizeof(int),1,f);
		puts("Продолжить? (y/n)");
	} while(getch()!='n');
	fclose(f);
}

int main()
{
	setlocale(LC_ALL,"rus");
	do
	{
		puts("1 - print\n2 - Reverse\n3 - input\n0 - exit");
		switch(getch())
		{
			case '1': printFile(FNAME); break;
			case '2': Reverse(FNAME); break;
			case '3': inputFile(FNAME); break;
			case '0': return 0;
	}
	} while(1);
}