#include <iostream>

using namespace std;

const int MAX_SIZE{10};

void PassByValue(int x);
void PassByReference(int & x);
void PassByConstantReference (const int & x);
void PassByPointer(int data[], int size);
void PassByConstPointer(const int data[], int size);

// utility function, ignore
void PrintArray(const int data[], int size);

int main() {

     int a{100};
     int myArray[MAX_SIZE]{1,2,3,4,5,6,7,8,9,10};
     const int constArray[MAX_SIZE]{1,2,3,4,5,6,7,8,9,10};
   
     cout << "In main" << endl;
     cout << "\tMain: a = " << a << endl;
     cout << "\tCalling PassByValue(a)" << endl;   
     cout << endl;

     PassByValue(a);
    
     cout << endl;
     cout << "Back in Main: " << endl;
     cout << "\tMain: a = " << a << endl;
     cout << "\tCalling PassByReference(a)" << endl;
     cout << endl;

     PassByReference(a);

     cout << endl;
     cout << "Back in Main: " << endl;
     cout << "\tMain: a = " << a << endl;
     cout << "\tCalling PassByConstReference(a)" << endl;
     cout << endl;

     PassByConstantReference(a);

     cout << endl;
     cout << "Back in Main: " << endl;
     cout << "\tMain: a = " << a << endl;

     cout << "\tThe array is " ;
     PrintArray(myArray, 10);
     cout << "Calling PassByPointer(myArray, 10)" << endl;
     cout << endl;

     PassByPointer(myArray, 10);

     cout << endl;
     cout << "Back in Main: " << endl;
     cout << "\tThe array is " ;
     PrintArray(myArray, 10);
     cout << "Calling PassByConstPointer(myArray, 10)" << endl;
     cout << endl;

     PassByConstPointer(myArray, 10);

     cout << endl;
     cout << "Back in Main: " << endl;
     cout << "\tThe array is " ;
     PrintArray(myArray, 10);
     cout << endl;


     // some experiments with constants
     PassByValue(100);
     //PassByReference(100);
     PassByConstantReference(100);
     //PassByPointer(constArray,10);
     //PassByConstPointer(constArray,10);
     PrintArray(constArray,10);

     return 0;
}

void PassByValue(int x){
    cout << "In PassByValue" << endl;
    cout <<"\tx = " << x << endl;
    x = -999;
    cout << "\tSetting x to be " << x << endl;

    return;
}

void PassByReference(int & x) {
    cout << "In PassByReference" << endl;
    cout <<"\tx = " << x << endl;
    x = -999;
    cout << "\tSetting x to be " << x << endl;

    return;
}

void PassByConstantReference (const int & x){
    cout << "In PassByConstantReference" << endl;
    cout <<"\tx = " << x << endl;
    // The next line may be commented out so the program will compile.
    //x = 10;
    cout << "\tSetting x to be " << x << endl;

    return;
}

void PrintArray(const int data[], int size){
    int i;

    if (size > 0) {
        cout << data[0];
        for(i = 1; i < size; ++i) {
           cout << ", " << data[i];
        }
        cout << endl;
    }

    return;
}

void PassByPointer(int data[], int size) {
    int i;

    cout << "In PassByPointer" << endl;
    cout << "\tthe array is ";
    PrintArray(data,size);

    for(i = 0; i < size; ++i) {
        data[i] = data[i] + 10;
    }
    cout << "\tAfter adding 10  to each element " << endl;
    cout << "\tthe array is ";
    PrintArray(data,size);

    return;
}

void PassByConstPointer(const int data[], int size) {
    int i;

    cout << "In PassByPointer" << endl;
    cout << "\tthe array is ";
    PrintArray(data,size);

    for(i = 0; i < size; ++i) {
        // The next line might be commented out so the code will compile
        //data[i] = data[i] + 10;
    }
    cout << "\tAfter adding 10  to each element " << endl;
    cout << "\tthe array is ";
    PrintArray(data,size);

    return;
}