Pearson Chapter 7 - 2 Programming Question

[castlyvania]

Hi there! My code seems to run fine with the one exception of not showing January as the month with least rainfall. Here are what the challenge specifies:

Write a program that lets the user enter the total rainfall for each of 12 months (starting with January) into an array of
doubles.
Once the user has entered the rainfall for all the months, the program should calculate and display (in this order):

The total rainfall for the year
The average monthly rainfall
The months with the highest and lowest amounts

Note:
Numeric values should be displayed using default precision. Do not use format specifiers to specify precision.
Input Validation:
Do not accept a negative number for any of the monthly rainfall amounts. If the user enters a negative value, the program should print the following string (exactly as it is shown here):
"invalid data (negative rainfall) -- retry"
and then immediately read the value again as input.
The following sample run shows how your program's output must appear. The user's input is shown in bold.

Here's what I've got so far:

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;

int main()
{
	const int MONTHS = 12;
	string name[MONTHS] = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };
	int i = 0;
	double rainfall[MONTHS];
	double total = 0, avg = 0, highRain = 0, lowRain = 0;
	string highMonth;
	string lowMonth;

	for (int i = 0; i < MONTHS; i++)
	{
		cout << "Enter rainfall for " << name[i] << ": " << endl;
		cin >> rainfall[i];
		while (rainfall[i] < 0)
		{
			cout << "invalid data (negative rainfall) -- retry" << endl;
			cin >> rainfall[i];
		}
		total += rainfall[i];
	}

	avg = total / 12;

	highRain = rainfall[0];

	for (int i = 1; i < MONTHS; i++)
	{
		if (rainfall[i] > highRain)
		{
			highMonth = name[i];
			highRain = rainfall[i];
		}
	}

	lowRain = rainfall[0];
	for (int i = 1; i < MONTHS; i++)
	{
		if (rainfall[i] < lowRain)
		{
			lowMonth = name[i];
			lowRain = rainfall[i];
		}
	}

	cout << "Total rainfall: " << total << endl;
	cout << "Average : " << avg << endl;
	cout << "Least rainfall in: " << lowMonth << endl;
	cout << "Most rainfall in: " << highMonth << endl;




	return 0;
}

I appreciate anyone that might be able to help!

[salem c]

> highRain = rainfall[0];
If you're going to do this here, then you also need to do
highMonth = name[0];


Or you force the if to evaluate on the first iteration by doing something like
highRain = -1E9;
And start the loops at 0 rather than 1.

Eg.

	highRain = -1E9;
	for (int i = 0; i < MONTHS; i++)
	{
		if (rainfall[i] > highRain)
		{
			highMonth = name[i];
			highRain = rainfall[i];
		}
	}

	lowRain = 1E9;
	for (int i = 0; i < MONTHS; i++)
	{
		if (rainfall[i] < lowRain)
		{
			lowMonth = name[i];
			lowRain = rainfall[i];
		}
	}

[thmm]

On L44 the if statement will not be executed if the lowest rainfall is in January, so lowMonth will be empty.
To fix it add lowMonth = name[0]; on L 42.

BTW. You can determine min and max rainfall when you read the values.
No need for the 2 loops at the end.

[seeplus]

You just need an index to the months with the least and most rainfall. Perhaps:

#include <iostream>
#include <string>

int main() {
	constexpr unsigned MONTHS { 12 };
	const std::string name[MONTHS] { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" };
	double rainfall[MONTHS] {};
	double total {};
	unsigned highMonth {}, lowMonth {};

	for (unsigned i {}; i < MONTHS; ++i) {
		std::cout << "Enter rainfall for " << name[i] << ": ";

		do std::cin >> rainfall[i];
		while (rainfall[i] < 0 && (std::cout << "Invalid data (negative rainfall) -- retry: "));

		total += rainfall[i];

		if (rainfall[i] > rainfall[highMonth])
			highMonth = i;

		if (rainfall[i] < rainfall[lowMonth])
			lowMonth = i;
	}

	std::cout << "Total rainfall: " << total << '\n';
	std::cout << "Average : " << total / MONTHS << '\n';
	std::cout << "Least rainfall in: " << name[lowMonth] << '\n';
	std::cout << "Most rainfall in: " << name[highMonth] << '\n';
}