Advent-of-Code/2021/day1/solution-part2.c

#include <stdio.h>

int countLines(char filename[]){
	FILE *fp;
	fp=fopen(filename, "r");
	long int lines =0;

	if ( fp == NULL ) {
		return -1;
	}

	while (EOF != (fscanf(fp, "%*[^\n]"), fscanf(fp,"%*c")))
		++lines;

	fclose(fp); // closing file
	return lines;
}

int main( int argc, char *argv[] ){
	if( argc == 2 ) {
		// 1 less because file ends with trailing new line
		int lines=countLines(argv[1]);
		int values[lines];
		int line=0;
		FILE *fp=fopen(argv[1], "r");
		int increasing = 0;

		// Read the values into an array
		while (!feof (fp)){
			fscanf(fp, "%d\n", &values[line]);


			if ( (line >= 3) && (values[line] > values[line-3]) ){

				increasing++;
				
			}


			line++;
		}
		fclose(fp); // closing file



		printf( "Increasing: %d\n", increasing );
	

		return 0;
	} else {
		printf("You need to provide a file\n");
		return 1;
	}
}