add, average and reverse in 1 function

[Vinz24]

the codes run it is i want. But the problem is how to make the addition, average and reverse will be in one function?

#include<iostream>
#include<stdlib.h>

int addition(int size, int a[]);

using namespace std;

int main ()
{
    int arr[20];
    int sz, i=0;
    double sum= 0;

    cout<<"How many numbers you want to be added? \n";
    while(!(cin>>sz))
    {
        cout<< "Invalid input! Please enter number only "<<endl;
        system("PAUSE");
        system("CLS");
        cin.clear();
        cin.ignore(10000, '\n');
        cout<<"How many numbers you want to be added? \n";
    }
    cout<< "Enter "<<sz<< " numbers: \n"<<endl;

    while(i<sz)
    {
        while(!(cin>>arr[i]))
        {
            cout<< "Invalid input! Please enter number only "<<endl;
            cin.clear();
            cin.ignore(10000, '\n');
        }
        i++;
    }

    system("CLS");

    cout<< "The inputed numbers are: "<<endl;

    for(int i= 0; i<sz; i++)
    {
        cout<<arr[i]<< " ";
    }

    sum= addition(sz, arr);
    double avg= sum/sz;

    cout<<endl<< "\nSum= "<<sum<<endl;
    cout<<endl<< "Average= "<<avg<<endl;

    cout<< "\nThe reverse of the inputed numbers are: "<<endl;

    for(int j=sz-1; j>-1; j--)              //for reversing the entered variable
    {
        cout<<arr[j]<< " ";
    }
    return 0;
}
int addition(int size, int a[])
{
    double sum= 0;
    for(int j= 0; j<size; j++)
    {
        sum+=a[j];
    }
    return sum;
}

The inputed numbers are:
4 3 5 2 1

Sum= 15

Average= 3

The reverse of the inputed numbers are:
1 2 5 3 4

[Manga]

#include<iostream>
#include<stdlib.h>

void arrayfunction(int size, int a[]); //make it a void function

using namespace std;

int main()
{
	int arr[20] = {};
	int sz, i = 0;
	double sum = 0;

	cout << "How many numbers you want to be added? \n";
	while (!(cin >> sz))
	{
		cout << "Invalid input! Please enter number only " << endl;
		system("PAUSE");
		system("CLS");
		cin.clear();
		cin.ignore(10000, '\n');
		cout << "How many numbers you want to be added? \n";
	}
	cout << "Enter " << sz << " numbers: \n" << endl;

	while (i<sz)
	{
		while (!(cin >> arr[i]))
		{
			cout << "Invalid input! Please enter number only " << endl;
			cin.clear();
			cin.ignore(10000, '\n');
		}
		i++;
	}

	system("CLS");

	//now that you have your array, pass it into your function.
	arrayfunction(sz, arr);
	
	cin.ignore();
	cin.get();
	return 0;
}

//put all your fun code into your function
void arrayfunction(int size, int a[])
{

	cout << "The inputed numbers are: " << endl;
	for (int i = 0; i < size; i++) {
		cout << a[i] << " ";
	}
	cout << endl << endl;

	cout << "The sum of the numbers is: ";
	int sum = 0;
	for (int i = 0; i < size; i++) {
		sum += a[i];
	}
	cout << sum << endl << endl;

	cout << "The average is: ";
	double avg = (double)sum / (double)size;
	cout << avg << endl << endl;

	cout << "The reverse order is: ";
	for (int i = size-1; i > -1; i--) {
		cout << a[i] << " ";
	}
	cout << endl << endl;
	
}

[Vinz24]

thanks but i want the body of the function has no cout or cin.

[elohssa]

You can just copy std::reverse and tweak it a little bit. Then can do everything in 1 loop.
http://en.cppreference.com/w/cpp/algorithm/reverse

https://wandbox.org/permlink/jVrLYzaLh0ds77ea

[keskiverto]

In other words you want a single function to compute and "return" three things:
1. Sum
2. Average
3. Change the order of values in the array

A function can return only one value. However,

Read section Arguments passed by value and by reference from http://www.cplusplus.com/doc/tutorial/functions/
and section Arrays as parameters from http://www.cplusplus.com/doc/tutorial/arrays/

What is not clear in the latter that function can modify caller's array similarly to by reference parameters:

#include <iostream>

using std::cout;

void printarray( const int arg[], size_t length ) {
  for (size_t n=0; n<length; ++n)
    cout << arg[n] << ' ';
  cout << '\n';
}

void iota( int arg[], size_t length, int first = 0 ) {
  for (size_t n=0; n<length; ++n) {
    arg[n] = first;
    ++first;
  }
}

int main ()
{
  constexpr size_t N {4};
  int firstarray[N] {};
  iota( firstarray, N, 42 );  // modifies firstarray
  printarray( firstarray, N );
}

[Manga]

ok to do what you want, you will need to put a switch statement into your function and include a third parameter that will tell the function which output to use. Then you will have to make repeating calls to your function, each with a different switch statement value.

[Vinz24]

can i use recursion to this? if so, how to do it? in order to have 1 function only? also all the cout or cin is in the main function only.

#include<iostream>
#include<stdlib.h>
using namespace std;
int addition(int);
double average(int);
int reverse(int);
int main()
{
    int val, count=0;

    cout << "Enter a number that has minimum of 4 digits and maximum of 9: \n";
    while(!(cin >> val) || val<=1000 || val>1000000000)
    {
        cout << "The value you inputed is invalid! Please try again."<<endl;
        system("PAUSE");
        system("CLS");
        cin.clear();
        cin.ignore(10000, '\n');
        cout << "Enter a number : \n";
    }

    int sum= addition(val);
    double avg= average(val);
    cout <<endl<< "Sum= " << sum<<endl;
    cout <<endl<< "Average= "<<avg<<endl;
    cout <<endl<< "The reverse of the inputed numbers are: "<<endl;
    cout <<endl<<reverse(val)<<endl;
}
int addition(int v)
{
    int num=v, sum=0, count=0;

    while (num != 0)
    {
        sum = sum + num % 10;
        num = num / 10;
        count++;
    }
    return sum;
}

double average(int v)
{
    int num=v, sum=0, count=0;

    while (num > 0)
        {
            sum = sum + num % 10;
            num = num / 10;
            count++;
        }
        double avg= (double)sum/(double)count;
    return avg;
}

int reverse(int v)
{
    int num=v, reversedNumber = 0, remainder, count=0;;

    while(num > 0)
    {
        remainder = num%10;
        reversedNumber = reversedNumber*10 + remainder;
        num = num / 10;
        count++;
    }
    return reversedNumber;
}

[Manga]

I don't think recursion could work for this. You see, once a function returns a value, the program jumps out of the function. So any attempt to recursive call the function after return, would be skipped.

[keskiverto]

No recursion. No switch. Do all three operations and return all results in one go:

//put compute code into your function
void arrayfunction( size_t size, int arr[], int & sum, double & average )
{
  // calculate sum
  // calculate average
  // rearrange elements of arr
}

[Manga]

Yes, but what if you wanted to pass a different array into the function each time. Then you would have to have a different sum variable and a different average variable for each array.

[keskiverto]

Bah humbug, I just want numbers to show:

int total {};
double avg {};

constexpr size_t foos {7};
int foo[ foos ];
// fill foo
// ...
arrayfunction( foos, foo, total, avg );
// show
std::cout << total << ' ' << avg;
for ( auto x : foo ) std::cout << ' ' << x;
std::cout << '\n';


constexpr size_t bars {42};
int bar[ bars ];
// fill bar
// ...
arrayfunction( bars, bar, total, avg );
// show
std::cout << total << ' ' << avg;
for ( auto x : bar ) std::cout << ' ' << x;
std::cout << '\n';

// just first half of bar
arrayfunction( bars/2, bar, total, avg );
// show
std::cout << total << ' ' << avg;
// ...