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

// Visual Studio: to skip warning message for safe functions.
// Else delete pragma.
#pragma warning(disable:4996)

float next_data(FILE* source);
void append_info(FILE* source, FILE* dest);

int main()
{
	FILE* output_file = fopen("output.txt", "a");

	while (1)
	{
		char file_path[512];
		printf("\nEnter filepath to read values from or 'n' to quit: \n");
		scanf("%s", file_path);

		if (file_path[0] == 'n')
			break;

		FILE* source_file = fopen(file_path, "r");
		if (!source_file)
		{
			printf("\nNo such file!\n");
			break;
		}

		append_info(source_file, output_file);
		fclose(source_file);
	}


	fclose(output_file);
	return EXIT_SUCCESS;
}

float next_data(FILE* source)
{
	float input = 0;
	fscanf(source, "%f", &input);

	return input;
}

void append_info(FILE* source, FILE* dest)
{
	float min = FLT_MAX, max = -FLT_MAX; // no std::numeric_limits so fuck this language tbh
	float sum = 0, avg = 0;
	size_t elem_count = 0;

	while(!feof(source))
	{
		float curr = next_data(source);
		++elem_count;

		if (curr < min)
			min = curr;
		if (curr > max)
			max = curr;

		sum += curr;
	}

	if (!elem_count)
	{
		fprintf(dest, "%s", "\nNo data.\n");
		return;
	}

	avg = sum / elem_count;
	fprintf(dest, "min: %f, max: %f, avg: %f\n", min, max, avg);
}