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

int main(int argc, char *argv[])
{
	if (argc < 2 || argc >4)
	{
		printf("Usage: ./avg <filename> <number of lines> <start line>\n");
		exit(0);
	}
	char *filename = argv[1];
	int numberOfLinse = -1;
	int startLine = 0;

	if (argc >= 3)
		numberOfLinse = atoi(argv[2]);
	if (argc == 4)
		startLine = atoi(argv[3]);

	printf("file is %s, startline is %d and linecount is %d \n", filename, numberOfLinse, startLine);
	long total = 0;
	int lines = 0;

	FILE *fp = fopen(filename, "r");
	if (fp == NULL)
	{
		printf("unable to open the file \n");
		exit(0);
	}

	char string[256];
    int i = 0;
	if (startLine != 0)
	{
		printf("moving the starting position by the specified lines \n");
		for (i = 0; i < startLine; i++)
		{
			if (fgets(string, 256, fp) == NULL)
			{
				printf("startline way too long \n");
				exit(0);
			}
		}
	}

	if (numberOfLinse == -1)
		numberOfLinse = 100000;

	for(lines = 0; lines < numberOfLinse; lines++)
	{
		if (fgets(string, 256, fp) == NULL)
			break;
		total += (long)strtod(string, NULL);
	}
	printf("Lines = %d, Total = %ld Avg = %ld \n", lines, total, total/lines);
}