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

/*
    Too Long Didn't Read program.
    Let n = int(argv[2]);
    This program will print the first and the last n lines of a file

    Might sound simple, but might help somebody.
*/
int main(int argc, char* argv[]){

//check arguments
    if(argc > 3){
        printf("Too much argumets\nsyntax: tldr file.ext inser_natural_number_here\n");
        return 1;
    }
    if(argc < 3){
        printf("Too few argumets\nsyntax: tldr file.ext inser_natural_number_here\n");
        return 1;
    }

//open file
    FILE *fp;
    if((fp = fopen(argv[1], "r")) ==  NULL){
        printf("Error opening file\n");
        return 1;
    }
    else{
        int c, i, j;
    //Count how many new line are there in the file.
        for(c = i = j = 0; (c = getc(fp)) != EOF && c != '\0';)
            if(c == '\n')
                j++;
    //What if user asks more than there is?
        if((atoi(argv[2])) > j){
            printf("File has only %d lines, you asked for %d, just open the file normally\n", j, atoi(argv[2]));
            return 1;
        }
    //Since I am still not comfortable with fsetpos. I just reset the index.
        if((fp = fopen(argv[1], "r")) ==  NULL){
            printf("Error opening file\n");
            return 1;
        }
    //Print the first n lines.
        for(c = i = 0; i < atoi(argv[2]);){
            c = getc(fp);
            putchar(c);
            if(c == '\n')
                i++;
        }
    //increment index i until it's at the start of the last n lines.
        for(i = i; i < (j-atoi(argv[2]));){
            if((c = getc(fp)) == '\n')
                i++;
        }
    //Print them.
        while((c = getc(fp)) != EOF)
            putchar(c);
    }
    fclose(fp);
    return 0;
}