将数组传递给函数时遇到问题

Question

I am supposed to use a string array to output the line "Enter rainfall for x", x being the name of a month, and having the input be sent to a separate array for calculations. Currently, when I run my code I am seeing "Enter rainfall for 1", "Enter rainfall for 2", etc. instead of "Enter rainfall for January", "Enter rainfall for February". Aside from this, the code also needs to show the total, average, and lowest and highest months of rainfall. I am able to have the program output the correct total and average however, the highest and lowest month just outputs a random number instead of a month name.

I have attempted to create prototypes and call an array to a function but I think the issue might be contributed to the fact that I am having issues with my string array. I have tried using a for loop, I've tried changing my syntax to no avail. I don't currently get any errors in the debugging process only see incorrect output instead of a string output.

#include <iostream>
#include <string>

using namespace std;

// Function Prototypes
void getMonthlyRainfall(double[], int);
double getTotal(const double[], int);
double getHighestAmount(const double[], int);
double getLowestAmount(const double[], int);

int main()
{
    const int MONTHS = 12;
    string monthNames[MONTHS] = { "January", "February", "March", "April", 
    "May", "June", "July", "August", "September", "October", "November", 
    "December" };
     double rainfall[MONTHS], // Array
        total,
        average,
        lowestAmount,
        highestAmount;

    //Get rainfall input from user
    getMonthlyRainfall(rainfall, MONTHS);

    // Get the total amount of rain for the year
    total = getTotal(rainfall, MONTHS);

    // Get the average rainfall
    average = total / MONTHS;

    // Get the month with the lowest rainfall
    lowestAmount = getLowestAmount(rainfall, MONTHS);

    // Get the month with the highest rainfall
    highestAmount = getHighestAmount(rainfall, MONTHS);

    cout << "Total rainfall: " << total << endl;
    cout << "Average rainfall: " << average << endl;
    cout << "Least rainfall in: " << getLowestAmount << endl;
    cout << "Most rainfall in: " << getHighestAmount << endl;
    return 0;
}

void getMonthlyRainfall(double rain[], int size) 
{
    int index;
    for (index = 0; index < 12; index++)
    {
        cout << "Enter rainfall for " << (index + 1) << ": ";
        cin >> rain[index];
    }
}

double getTotal(const double numbers[], int size) 
{
    double total = 0; // Accumulator
    for (int count = 0; count < size; count++)
        total += numbers[count];
    return total;
}

double getHighestAmount(const double numbers[], int size) 
{
    double highest; // Holds highest value
    // Get array's first element
    highest = numbers[0];
    // Step through array
    for (int count = 0; count < size; count++) 
    {
        if (numbers[count] > highest)
            highest = numbers[count];
    }
    return highest;
}

double getLowestAmount(const double numbers[], int size) 
{
    double lowest; // Holds lowest value
    // Get array's first element
    lowest = numbers[0];
    // Step through array
    for (int count = 0; count < size; count++)
    {
        if (numbers[count] < lowest)
            lowest = numbers[count];
    }
    return lowest;
}

As I stated the first output should say the actual name of a month and it should be in order. For instance, the prompt should first ask the user to input total rainfall for the month of January, the user inputs a number. The prompt then goes on to ask the user input a number for February, so on and so forth until December. I am instead seeing the prompt ask the user to input total rainfall for "1", user inputs a number, the prompt then asks user to input rainfall for "2" until it gets to 12. The program does the calculations and outputs correct total and average but when it is supposed to output "Month with highest (or lowest) rainfall: (Month name)" it instead gives me a random number such as 01201686.

So to sum up, the string array outputs month name and the user input is stored in a separate array for calculations. Those calculations are outputted for total and average but the rainfall totals need to be compared to the month with the corresponding entity and the output for highest and lowest then needs to be a string not a number.

Answer 1

It's a simple confusion over names. You have the name of the function (which will print as a 'random' number) instead of the name of the variable you are using.

cout << "Least rainfall in: " << getLowestAmount << endl;

should be

cout << "Least rainfall in: " << lowestAmount << endl;

As for your first quesiton, change

cout << "Enter rainfall for " << (index + 1) << ": ";

to

cout << "Enter rainfall for " << monthNames[index] << ": ";

Obviously the first version prints a number ( index + 1 is a number). To get the month name you have to use the number as an index to your array of month names.

To make this work you also will need to make monthNames available in the getMonthlyRainfall function (at the moment it's only visible in main ). You should pass monthNames to the getMonthlyRainfall function like this

void getMonthlyRainfall(double[], string[], int);

and

//Get rainfall input from user
getMonthlyRainfall(rainfall, monthNames, MONTHS);

and

void getMonthlyRainfall(double rain[], string monthNames[], int size) 
{
    ...

EDIT

So to output both lowest monthly rainfall and the name of the month with the lowest rainfall you should change your getLowestAmount function to return the index of the month with the lowest rainfall. You should also change the name of this function because it's now doing something different from the original function and the old name does not accurately describe the new function, but for clarity I'll leave it the same. You can decide on a new name later.

// this function returns a month index, not a rainfall amount,
// so it's return type is int not double
int getLowestAmount(const double[], int);

Here's the updated function

int getLowestAmount(const double numbers[], int size) 
{
    double lowest; // Holds lowest value
    int lowestIndex; // Holds the index of the lowest value
    // Get array's first element
    lowest = numbers[0];
    lowestIndex = 0;
    // Step through array
    for (int count = 0; count < size; count++)
    {
        if (numbers[count] < lowest)
        {
            lowest = numbers[count];
            lowestIndex = count;
        }
    }
    return lowestIndex;
}

See the function is the same except I've added lowestIndex and that's the value I return.

Now in main you can use the lowest index to print both values that you want to see

// Get the month with the lowest rainfall
lowestIndex = getLowestAmount(rainfall, MONTHS);

...

cout << "Least rainfall in: " << monthNames[lowestIndex] << 
    " is " << rainfall[lowestIndex] << endl;