https://www.reddit.com/r/cpp_questions/comments/2ufw69/problem_with_sorting_parallel_arrays/

simple.cpp

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

float read_rain(unsigned month);
float get_total(const std::vector<float>& data);
unsigned find_min(const std::vector<float>& data);
unsigned find_max(const std::vector<float>& data);

const int month_count = 12;
// there isn't a problem with a global array IF it is CONSTANT
const std::vector<std::string> month_names = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
                                              "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};

int main() {

	std::vector<float> rains;

	for (unsigned i = 0; i < month_count; i++) {
		rains.push_back(read_rain(i));
	}

	float total = get_total(rains);
	get_total(rains);
	std::cout << "The total rainfall was: " << total << "\n"
	          << "The average monthly rainfall was: " << total / month_count << "\n";

	unsigned min = find_min(rains);
	std::cout << month_names[min] << " had the least rain at: " << rains[min] << "\n";
	unsigned max = find_max(rains);
	std::cout << month_names[max] << " had the most rain at: " << rains[max] << "\n";
}

float read_rain(unsigned month) {
	std::cout << "Amount of rain for " << month_names[month] << ": ";
	float rain = 0;
	std::cin >> rain;
	std::cout << "\n";
	while (rain < 0) {
		std::cout << "Invalid Number, please enter again:\n";
		std::cin >> rain;
	}
	return rain;
}

float get_total(const std::vector<float>& data) {
	float total = 0;

	for (auto datum: data) {
		total += datum;
	}

	return total;
}

unsigned find_min(const std::vector<float>& data) {
	float min = data.front();
	unsigned min_index = 0;
	for (unsigned i = 1; i < month_count; ++i) {
		if (data.at(i) < min) {
			min = data.at(i);
			min_index = i;
		}
	}
	return min_index;
}

unsigned find_max(const std::vector<float>& data) {
	float max = data.front();
	unsigned max_index = 0;
	for (unsigned i = 1; i < month_count; ++i) {
		if (data.at(i) > max) {
			max = data.at(i);
			max_index = i;
		}
	}
	return max_index;
}