Entire array as argument example

[eiger3970]

Hi cplusplus.com forum. Could someone help me build this code into anything simple so that it works please.


#include <iostream>
using namespace std;

int main()
{
void fillUp(int a[], int size);
// Precondition: size is the declared size of the array a.
// The user will type in size integers.
// Postcondition: The array a is filled with size integers
// from the keyboard.

void fillUp(int a[], int size)
{
cout << "Enter " << size << " numbers:\n";
for (int i = 0; i < size; i++)
cin >> a[i];
cout << "The last array index used is " << (size - 1) << endl;
}
}

// Try to get this to work.

[vlad from moscow]

I would separate the code that provides entering of the array size and the code that provides filling of the array.

int get_size()
{
   std::cout << "Enter array size: ";
   int n;

   if ( ! ( std::cin >> n ) ) n = 0;

   return ( n );
}

int * create_array( int n )
{
   int *a = new intw[n];

   std::cout << "Enter " << n << " integer numbers: ";
   for ( int int i = 0; i < n; i++ ) std::cin >> a[i];

   return ( a );
}

and in the main they used the following way

int *a = create_array( get_size() );

delete [] a;

However as your array is declared in main then your code will look

#include <iostream>

using namespace std;

void fillUp( int a[], int size );
 
int main()
{
   const int N = 10;
   int a[N];

   fillUp( a, N );

   return 0;
}

 // Precondition: size is the declared size of the array a.
 // The user will type in size integers.
 // Postcondition: The array a is filled with size integers
 // from the keyboard.
 
void fillUp( int a[], int size )
{
   cout << "Enter " << size << " numbers:\n";
   for (int i = 0; i < size; i++)   cin >> a[i];

   cout << "The last array index used is " << (size - 1) << endl;
}

[S G H]

You cannot declare functions inside other functions:

#include <iostream>
using namespace std;

int main()
{
    void fillUp(int a[], int size); // Wrong!
    void fillUp(int a[], int size)  // Wrong!
    {
        cout << "Enter " << size << " numbers:\n";
        for (int i = 0; i < size; i++)
        cin >> a[i];
        cout << "The last array index used is " << (size - 1) << endl;
    }
}

#include <iostream>
using namespace std;
void fillUp(int a[], int size); // Right!
void fillUp(int a[], int size)  // Right!
{
    cout << "Enter " << size << " numbers:\n";
    for (int i = 0; i < size; i++)
    cin >> a[i];
    cout << "The last array index used is " << (size - 1) << endl;
}
int main()
{
    //...
}

[vlad from moscow]

@EssGeEich

You cannot declare functions inside other functions:

It is a wrong statement. Any function may be declared in another function. A function may not be defined in other function.

So the code

int main()
{
    void fillUp(int a[], int size);

is valid

[S G H]

It is a wrong statement. Any function may be declared in another function. A function may not be defined in other function.

Didn't know about that, gonna trust you on the word, but he still defined the function into main...