//********************************************************************
// 
// SentinelLoop.java
//
//********************************************************************

   import cs1.Keyboard;
public class SentinelLoop
{

   //-----------------------------------------------------------------
   //  A comment that must be replaced by comment(s) describing the    //  program's main method.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
// Program SentinelLoop prompts the user for an integer number,
// reads the number, and adds it into a sum.
// The loop continues until the user types a negative number.
// Then the sum is printed.
// ============================================================

// The following comment statements describe the program design 
// steps necessary to write this program
// BUT THEY ARE NOT IN THE CORRECT ORDER!!!
// Do the following:
// 1. Figure out the correct design solution for this program using the
//    steps in each of the comments below.  It's best to write this
//    down on paper rather than starting to edit your Java source file.
// 2. Using the JCreator editor copy and paste the Java comment lines
//    below into their proper order in your source file.
// 3. After each comment add the Java statement (or statements) that
//    does what each comment says
// 4. Compile, execute, and test your program.
// ==> Some of these design steps may be used more than once.

	
	// variable for acculumating the sum (a declaration statement)
	// variable for storing the user's input value  (a declaration statement)
    int sum,value; 
	sum = 0;		// initialize sum to zero
    
    // Prompt the user by printing a message such as,
    //       "Enter an integer value; press return."
    //       "To signal end of the input, enter a negative value."
    System.out.println ("Enter an integer value; press return. \n To signal end of the input, enter a negative value.");
    // Read the user's input value
	value = Keyboard.readInt();
	
	// main loop
    while ( value >= 0 )    // (fill in the missing Loop Termination Condition, LTC)
    {
    
    	// Add the input value to the running sum
		sum += value;
    
		// Prompt the user by printing a message such as,
    	//       "Enter an integer value; press return."
    	//       "To signal end of the input, enter a negative value."
    	System.out.println ("Enter an integer value; press return.\nTo signal end of the input, enter a negative value.");
    	// Read the user's input value
		value = Keyboard.readInt();
	                                                
    }
    
	// Print the value of sum (including a label such as, "The sum is ")
	System.out.println ("The sum is " + sum);

   } //end main

} // end class SentinelLoop

//The program printed the same line as many times as numbers entered separated by a space
//because it ran the loop that many times and reentered the value of the numbers into the 
//integer variable value