How would you call data from main and pass it to a function? (C++)

Question

So I have trouble calling data from main function (an array with variables you input) and wasn't sure how to pass it to a float getTotal function. Here is my code:

#include <iostream>
#include <iomanip>

using namespace std;

float getTotal(float [], int )
   {
     double total = 0;
     for (int i=1; i<ARRAYSIZE; i++)
        {
           total += inputs[i];
        }
     cout << "The total rainfall for the year is " << total << "inches." << endl;
     return total;
   }

float getAverage(float [], int)
   {
     //code goes here
   }

int main()
   {
     const int ARRAYSIZE = 13;
     int inputs[ARRAYSIZE], i=1;
     do
        {
           cout << "Enter the rainfall (in inches) for month #" << i << ": ";
           cin >> inputs[i];
           if ( inputs[i] < 0 )
              {
                  cout << "Please enter a non-negative number for rainfall in month " << i << " :";
                  cin >> inputs[i];
              }
           i++;
        }
     while (i < 13);

     float getTotal(float inputs[], int ARRAYSIZE);
     float getAverage(float inputs[], int ARRAYSIZE);
   }

So I want to call the array data from main and calculate the total in the getTotal section. I've tried various ways, none of which worked.

Which are you having trouble with, populating an array in `main`, or passing an array to a function? — Beta, Oct 21 '13 at 05:16
If possible, use an `std::vector` instead of an array. Right now, you're trying to use `ARRAYSIZE` in `getTotal`, but it's local to `main`, so it's not visible in `getTotal`. You also want to give names to the parameters so you can access them inside `getTotal`. — Jerry Coffin, Oct 21 '13 at 05:17
@ Above I have trouble passing the array to a function, so I can calculate the total in the getTotal function @Jeffry, can you give me an example please? — Imran Chowdhry, Oct 21 '13 at 05:24

score 0 · Answer 1 · answered Oct 21 '13 at 05:20

0

float getTotal(float inputs[], int ARRAYSIZE)
   {
     double total = 0;
     for (int i=1; i<ARRAYSIZE; i++)
        {
           total += inputs[i];
        }
     cout << "The total rainfall for the year is " << total << "inches." << endl;
     return total;
   }

float getAverage(float inputs[], int ARRAYSIZE)
   {
     //code goes here
   }

int main()
   {
     const int ARRAYSIZE = 13;
     int inputs[ARRAYSIZE], i=1;
     do
        {
           cout << "Enter the rainfall (in inches) for month #" << i << ": ";
           cin >> inputs[i];
           if ( inputs[i] < 0 )
              {
                  cout << "Please enter a non-negative number for rainfall in month " << i << " :";
                  cin >> inputs[i];
              }
           i++;
        }
     while (i < 13);

     float fTotal = getTotal(inputs, ARRAYSIZE);
     float fAverage = getAverage(inputs, ARRAYSIZE);
   }

answered Oct 21 '13 at 05:20

t_smith

89
1
1
7

Here is my new and updated code, will paste the errors I get also. I'm unsure why this happens? Code: http://puu.sh/4VqJv.png The errors I get are found on this puu.sh link. http://puu.sh/4VqHi.png – Imran Chowdhry Oct 21 '13 at 05:35
EDIT: Errors are here, updated and fixed a small mistake. http://puu.sh/4VqNI.png – Imran Chowdhry Oct 21 '13 at 05:36
You didn't declare i in the function getTotal. Your errors are because you don't understand scope. Here's a quick [reference](http://msdn.microsoft.com/en-us/library/b7kfh662.aspx). A general rule is that a variable is only visible inside { } block, so other functions can't use any variable that is declared in main function block. – t_smith Oct 21 '13 at 06:23

Ismail Faruqi · Answer 2 · 2013-10-21T06:33:16.727

0

Replace your function declarations:

float getTotal(float [], int )
float getAverage(float [], int)

to this

float getTotal(int* inputs, int ARRAYSIZE)
float getAverage(int* inputs, int ARRAYSIZE)

And this line inside main() function:

float getTotal(float inputs[], int ARRAYSIZE);
float getAverage(float inputs[], int ARRAYSIZE);

to this

float getTotal(inputs, ARRAYSIZE);
float getAverage(inputs, ARRAYSIZE);

edited Oct 21 '13 at 06:33

answered Oct 21 '13 at 05:21

Ismail Faruqi

482
4
16

I did, got an error so I changed the code with this float fTotal = getTotal(inputs, ARRAYSIZE); float fAverage = getAverage(inputs, ARRAYSIZE); getting a "cannot convert parameter 1 from int[13] to float[] error now. – Imran Chowdhry Oct 21 '13 at 05:38
Sorry, I have edited my answer, let me know if the compiler still spits error. I am currently without a compiler :-( – Ismail Faruqi Oct 21 '13 at 05:58
no problem!! I appreciate the help!! It seems to have work, but I have to fix previous errors before confirming. Error I get now is error C2078: too many initializers Only error left this is on line float getTotal(inputs, ARRAYSIZE); – Imran Chowdhry Oct 21 '13 at 06:18
Replace the floats in function declaration with int; I have (again) updated my answer above :-) – Ismail Faruqi Oct 21 '13 at 06:36

score 0 · Answer 3 · answered Oct 21 '13 at 06:27

There is so many errors in our source code. example " int inputs[ARRAYSIZE] " . Your array is int data type but you are passing this array as float data type. there is a compiler
error. Second, you should declare function and its data type outside the main function but
you are doing inside the main function float getTotal(float inputs[], int ARRAYSIZE); there is another compiler error. While calling function you don't need to specify the data type of argument . So there is a possible code I have written , Hope it will help you.

#include <iostream>
#include <iomanip>

using namespace std;

float getTotal(int *inputs, int ARRAYSIZE )
  {
   double total = 0;
     for (int i=1; i<=ARRAYSIZE; i++)
      {
        total += inputs[i];
      }
      cout << "The total rainfall for the year is " << total << "inches." << endl;
  return total;

}

 float getAverage(int *inputs, int ARRAYSIZE)
    {
     //code goes here

    return 1.4;
   }

 int main()
    {
     const int ARRAYSIZE = 3;
     int inputs[ARRAYSIZE], i=1;
     do
       {
       cout << "Enter the rainfall (in inches) for month #" << i << ": ";
       cin >> inputs[i];
       if ( inputs[i] < 0 )
          {
             cout << "Please enter a non-negative number for rainfall in month " << i     
                 << " :";
              cin >> inputs[i];
          }
       i++;
    }
 while (i <= 3);

     getTotal(inputs, ARRAYSIZE);
     getAverage(inputs, ARRAYSIZE);

return 0;

}

     While calling function, the return value you can store in variable but data type of   

      variable should be the same of return type of the function 

      e.g  float a = getTotal(inputs, ARRAYSIZE);
     float b = getAverage(inputs, ARRAYSIZE);
      or you can directly call this function in cout output command statement.like

cout<< getTotal(inputs, ARRAYSIZE);

hmm, I have everything working except converting parameters 1 from int[13] to float[]. any help there? — Imran Chowdhry, Oct 21 '13 at 07:43
I think you need to see this link.Hope it will be useful for you [link](http://stackoverflow.com/questions/12344400/convert-int-to-float-in-c-no-casting) — Birendra Kumar, Oct 21 '13 at 12:04

GMasucci · Answer 4 · 2013-10-21T12:03:12.987

hi @user2901840 a slight modification in the code allows it to run fine:

#include <iostream>
#include <iomanip>

using namespace std;

float getTotal(float floatarray[], int size)
{
    float total = 0.0f;
    for (int i=0; i<size; i++)
    {
        total += floatarray[i];
    }
    return total;
}

float getAverage(float floatarray[], int size)
   {
        return (getTotal(floatarray, size))/size;
   }

int main()
   {
        int ARRAYSIZE = 12, i=0;
        float inputs[ARRAYSIZE];
        do
        {
            cout << "Enter the rainfall (in inches) for month #" << i << ": ";
            cin >> inputs[i];
            if ( inputs[i] < 0.0 )
                {
                    cout << "Please enter a non-negative number for rainfall in month " << i << " :";
                    cin >> inputs[i];
                }
            i++;
        }
        while (i < ARRAYSIZE);
        cout << "\n\nThe total rainfall for the year is " << getTotal(inputs, ARRAYSIZE) << " inches." << endl;
        cout << "The average rainfall per month during the year was: " << getAverage(inputs, ARRAYSIZE) << " inches."<< endl;
   }

You needed to predefine the classes correctly, and the calls needed to be modified. To clarify the code I have: - renumbered the i value to match common C++ conventions (running 0 to 11 for 12 values) - re-utilised functions to minimise code - re-declared the array as an array of floats (you initially had it as an array of ints)

Hope this helps:)

Let me know if you need more detail or explanation and I can fill in more information.

How would you call data from main and pass it to a function? (C++)

4 Answers4