Two or more solutions to code call-by-reference function parameter in C++

Two or more solutions:

//Solution 1: call-by-reference function parameter using 
//            ampersand sign &
void swap_values(int& variable1, int& variable2)
{
    int temp;
    temp = variable1;
    variable1 = variable2;
    variable2 = temp;
}
 
//Solution 2: call-by-reference function parameter using 
//            asterisk sign * or pointer syntax
void swap_values_asterisk(int *variable1, int *variable2)
{
    int temp;
    temp = *variable1;
    *variable1 = *variable2;
    *variable2 = temp;
}

//Solution 3: call-by-reference function parameter using 
//            a standard library function, put inside driver
void swap_values_stdLibraryFunction(int& variable1, int& variable2)
{
    swap(variable1, variable2); //put inside driver
}

//Solution 4: call-by-reference function parameter using array syntax
void swap_values_array(int array1[], int array2[])
{
    int temp;
    temp = array1[0];
    array1[0] = array2[0];
    array2[0] = temp;
}

Driver:

    int a, b;

    a=1;
    b=2;
    swap_values(a, b);
    cout << "a: " << a << ", b: " << b << endl;

    a=1;
    b=2;
    swap_values_asterisk(&a, &b);
    cout << "a: " << a << ", b: " << b << endl;

    a=1;
    b=2;
    swap_values_stdLibraryFunction(a, b);
    cout << "a: " << a << ", b: " << b << endl;

    int array_a[10];
    int array_b[10];
    array_a[0] = 1;
    array_b[0] = 2;
    swap_values_array(array_a, array_b);
    cout << "a: " << array_a[0] << ", b: " << array_b[0] << endl;


Program output:

a: 2, b: 1
a: 2, b: 1
a: 2, b: 1
a: 2, b: 1