// Mr. Minich
// CMPSC 201
// Ch. 4 Demo Program #3
// January 30, 2000 
// Purpose - to illustrate the use of the if statement

#include <iostream.h>

int main()
{
	int num1 = 1;   // used in if statement examples
	int num2 = 0;   // used in if statement examples

	if (num1 == 1)
	{  
		cout << "num1 is equal to 1" << endl;  
	}

    // Notice the use of blank lines above and below the if statement for the sake of readability.
 	
	num1 = 5;

	if (num1 = 1)
	{  
		cout << "num1 is equal to " << num1 << endl;  
	}

	// This prints "num1 is equal to 1". The programmer
	// incorrectly used the assignment operator (=) in the 
	// control expression instead of the relational operator
	// (==). This is a very common mistake and C++ yields a
	// TRUE to the result of the expression (num1 = 1).

	num1 = 1;
	num2 = 1;

	if ((num1 == 1) && (num2 == 1))
	{  
		cout << "num1 AND num2 are both equal to 1" << endl;  
	}
	else
	{  
		cout << "num1 AND num2 are not both equal to 1" << endl;  
	}

	num1 = 4;
	num2 = 5;

	if (num1 == 99 || num1 == 4 && num2 == 99)
	{  
		cout << "The control expression is TRUE." << endl;  
	}
	else
	{  
		cout << "The control expression is FALSE." << endl;  
	}

	// This prints "The control expression is FALSE." Remember the 
	// order of operations when evaluating logical operators.

	if (num1)
	{
		cout << "num1 is a nonzero value." << endl;
	}

	// As long as the variable num1 is a positive value, the control
	// expression (num1) yields a TRUE.

	return 0;
}// end of main