Passing Arrays

Passing One Dimensional Arrays to Functions

Before we get into passing arrays, let's review the format for using functions.

Now, let's take a closer look at how those arrays are passed. In C++, arrays are not passed by value to functions, they are passed by reference. Because of this, you do not have to use the & reference character. You simply pass the base address of an array to a function. To do this, just supply the name of the array.

For example, suppose you had made the following declarations:
const int size=10; int ary[size];

Further suppose you wanted to pass this array to a function called getMax which expected the array reference as a parameter. The call to that function would be:
getMax(ary, size);

Notice that only the array name ary appears in the parameter list; it is not followed by any subscripts at all.

Example:

This program adds two integer arrays and displays the arrays.

// Program Arraypractice.cpp will add two arrays and store the sum
// in the third array.  Print them all out to the screen.

#include <iostream>
using namespace std;

void addArrays(int[], int[], int[], int);

int main()
{
    const int MAX_ARRAY = 5;

int a[MAX_ARRAY];
    int b[MAX_ARRAY];
    int c[MAX_ARRAY];
    int index;

// Ask users to enter values for array a[].
    cout << "Please input 5 values for a array." << endl;
    for (index = 0; index < MAX_ARRAY; index++)
    {
        cout << index + 1 << ": ";
        cin >> a[index];
    }

// Ask users to enters value for array b[].
    cout << "Please input 5 values for b array." << endl;
    ;
    for (index = 0; index < MAX_ARRAY; index++)
    {
        cout << index + 1 << ": ";
        cin >> b[index];
    }

// Store the sum of array a[] and array b[] to array c[].
    // for (index = 0; index < MAX_ARRAY; index++)
    // {

//    c[index] = a[index]+ b[index];
    // }

// call for the function addArrays() to add two arrays
    addArrays(a, b, c, MAX_ARRAY);

//To separate the output from other stuff
    cout << endl;

// Add code to print out each of the arrays
    for (index = 0; index < MAX_ARRAY; index++)
    {
        cout << "a[" << index << "] = " << a[index] << endl;
        cout << "b[" << index << "] = " << b[index] << endl;
        cout << "c[" << index << "] = " << c[index] << endl;
        cout << endl;
    }

return 0;
}

// a function adds two arrays
void addArrays(int x[], int y[], int z[], int len)
{
    for (int i = 0; i < len; i++)
    {
        z[i] = x[i] + y[i];
    }

return;
}

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