#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#define BLOCK_SIZE 1024
void main()
{
	char fname[10]="file";
	char *fno[] = {"1", "2", "3", "4", "5", "6", "7"};
	char *file;
	char buffer[BLOCK_SIZE];
	struct timeval start, end;
	int fd=0;
	int i, j;
	unsigned long long time;
	int status;
	for (i = 0; i < 7; i++) {
		file = strcat(fname, fno[i]);
	        printf("File %d: %s\n", i, file);
		fflush(NULL);
		fd = open(file, O_RDONLY);
		if (!fd) {
			printf("unable to open\n");
			exit(0);
		}
		while(read(fd, buffer, BLOCK_SIZE));
		lseek(fd, 0, SEEK_SET);
		gettimeofday(&start, NULL);
		for (j = 0; j < 10; j++) {
			while(read(fd, buffer, BLOCK_SIZE));
			lseek(fd, 0, SEEK_SET);
		}
		gettimeofday(&end, NULL);
		time = (end.tv_sec*1e6+end.tv_usec) - (start.tv_sec*1e6+start.tv_usec);
		printf("timestamp %llu - %llu\n", end.tv_sec*1e6+end.tv_usec, start.tv_sec*1e6+start.tv_usec);
		printf("time taken to read file # %d - %llu\n", i, time);
		sync();
		status = system("sudo /sbin/sysctl vm.drop_caches=3");
		sync();
		strcpy(fname, "file");
	}
	

}