// Mr. Minich
// CMPSC 101
// Ch. 1 Demo Program #5
// January 30, 2000 
// Purpose - to illustrate type coercion (aka promotion or implicit type conversion)
//		& type casting (explicit type conversion)

#include <iostream>
using namespace std;


int main()
{
	int int1 = 1;                   // int1 is declared and initialized in one statement 
        int int2 = 2;                   
	int int3;			// int3 is mistakenly not initialized
	double double1 = 0.0;
 	double double2 = 2.0;

	int3 = int1 + int2; 		// int3 = 3 (the whole number)
	cout << "int3 = " << int3 << endl;

	double1 = int1 + double2; 	// double1 = 3.0 (the decimal number)
	// this is an example of type coercion (aka promotion), where C++ automatically
	// promotes int1 (the whole number) to the double type in order
	// to be able to perform the addition of two doubles. Technically,
	// C++ cannot add an int to a double even though both are 4-bytes.

	cout << "double1 = " << double1 << endl;

	double2 = 1999.99;
	cout << "The price of the computer is $" << double2 << endl;

	cout << "The price of the computer is $" << int (double2) << endl;


	// type casting is used here by the programmer to 
	// force C++ to interpret double2 as an integer
	// resulting in the truncation of the value 1999.99 to simply 1999
	// The newer form of type casting in C++ is to use      static_cast <int>     as in:


	// cout << "The price of the computer is $" << static_cast <int> (double2) << endl;

	// Summary: Type coercion (promotion) is automatically used by the C++ compiler
	// to evaluate expressions while typecasting is explicitly
	// used by the programmer for whatever reason. Typecasting and 
	// type coercion are examples of mixing data types within the same statement.

	return 0;
}// end of main