Thread: keeping track of code blocks

In some (for me) longish programs that include some nested loops and if/else if/ else statements, I was having to scroll around quite a bit (even with canonical indentations) to figure out just what the various blocks were doing and whether I had the right number of brackets.

So, my spontaneous solution has been to immediately close an empty block with a bracket and a note describing what the block does. Example without any real code yet:

Code:

// loop for entering and validating Var
do
{
}
while (Val == 0); // closes do-while loop for entering and validating Var

After doing that, then I start writing the code inside the loop.

This seems to help (as a supplement to correct indentation practices), but I wondered if others have better suggestions. I thought this was another one worth asking as newbie just to try to develop good programming habits early.

Beyond simply factoring out code into other functions, preferring RAII, placing sentries at the correct level, and other generalities, some situations have specific ways to simplify nesting depth. (For example, propagating errors from immediate levels while returning to the parent block on success will sometimes clear a few levels.) Odds are if you are dealing with something *you've* written and resort to scrolling around you probably need a different approach to the problem you are trying to solve. (Or you need a reboot.) You could always ask for help with what you're doing now...

Soma

Originally Posted by brewbuck

Generally, if I can't see the opening and closing brace on the screen at the same time, I refactor the loop until I can.

Depends on how big your screen is!

what kind of screen do you think is suitable for it

As to IDE, I'm using MS Visual C++ Express. I also have Borland's Turbo C++ but couldn't figure out how to use it yet (I'm just developing 1 .cpp file at a time, and Borland, at least as far as I can tell at my currently primitive level, seems almost require that you know how to navigate around a project containing multiple .cpp code files, etc. I did notice that Borland fills in more than MS).

The problem may be the result of getting over-ambitious on exercises where I've tried to go beyond what "the book" (Gaddis, up to and including chap. 5) clearly wants on the exercise. For example, I'm imposing more strict validation than he presumably wants at this point (hence a previous question here), and I'm asking the user to confirm entries at certain strategic points in the program.

And... well, if you guys want to see some code, here goes. I won't claim that it's optimal efficiency, even restricting oneself to the portions of the language I currently know, but it does produce pretty much the desired result, and I can't see how to make the somewhat complex loop structure significantly more efficient with the stuff I know. But maybe you guys will see something I don't.

Here's the task (Gaddis, chap. 5, prog. challenge 15): Display a weekly payroll report given data for employee number, gross pay, state tax, federal tax, and FICA with various validations for gross pay and taxes (should be obvious from my code). Also, entering employee number 0 should act as a sentinel to terminate data entry and display the payroll report.

Here's my solution:

Code:

// payroll report

#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
	int Num;
	double Gross, TotGross = 0, State, TotState = 0, Fed, TotFed = 0,
		FICA, TotFICA = 0;
	bool Val = 0;
	char Conf = 'n';

	do
	{ 
// get employee number
		do
		{
			cout << "Enter employee number or \"0\" to end list: ";
			cin >> Num;
	// validate input
			while (cin.fail() || (Num < 0))
			{
				cin.clear();
				cin.ignore(100, '\n');
				cout << "Invalid input!\n\n"
					<< "Enter employee number or \"0\" to end list: ";
				cin >> Num;
			}
	// exit loop on 0 entry for employee number
			if (Num == 0)
			{
				cout << "\nAre you finished entering employee data (Y/N)? ";
				cin >> Conf;
			}
			if ((Num == 0) && ((Conf == 'Y') || (Conf == 'y')))
				Val = 1;
			else if (Num == 0)
				cout << endl; // mistaken 0 entry
			else
			{
	// confirm employee number
				cout << "Employee number is " << Num
					<< ". \nConfirm (Y/N): ";
				cin >> Conf;
				cout << endl;
		// get info only when confirmed; otherwise rerun employee num entry loop
				if ((Conf == 'Y') || (Conf == 'y'))
				{
					do
					{
		// gross pay
						cout << "Employee " << Num << " gross pay: ";
						cin >> Gross;
			// validate
						while (cin.fail() || (Gross < 0))
						{		
							cin.clear();
							cin.ignore(100, '\n');
							cout << "Invalid input!\n\n"
								<< "Employee " << Num << " gross pay: ";
							cin >> Gross;
						}
			
		// state tax
						cout << "\nEmployee " << Num << " state tax: ";
						cin >> State;
			// validate
						while (cin.fail() || (State < 0) || (State > Gross))
						{		
							cin.clear();
							cin.ignore(100, '\n');
							cout << "Invalid input!\n";
							if (State < 0)
								cout << "State tax cannot be negative.\n";
							if (State > Gross)
								cout << "State tax cannot exceed gross wages.\n";
							cout << "Employee " << Num << " state tax: ";
							cin >> State;
						}
			
		// federal tax
						cout << "\nEmployee " << Num << " federal tax: ";
						cin >> Fed;
			// validate 
						while (cin.fail() || (Fed < 0) || (Fed > Gross))
						{		
							cin.clear();
							cin.ignore(100, '\n');
							cout << "Invalid input!\n";
							if (Fed < 0)
								cout << "Federal tax cannot be negative.\n";
							if (Fed > Gross)
								cout << "Federal tax cannot exceed gross wages.\n";
							cout << "Employee " << Num << " federal tax: ";
							cin >> Fed;
						}
			
		// FICA
						cout << "\nEmployee " << Num << " FICA: ";
						cin >> FICA;

			// validate
						while (cin.fail() || (FICA < 0) || (FICA > Gross))
						{		
							cin.clear();
							cin.ignore(100, '\n');
							cout << "Invalid input!\n";
							if (FICA < 0)
								cout << "FICA cannot be negative.\n";
							if (FICA > Gross)
								cout << "FICA cannot exceed gross wages.\n";
							cout << "Employee " << Num << " FICA: ";
							cin >> FICA;
						}
			
		// validate
						if (State + Fed + FICA > Gross)
						{
							cout << "Total taxes cannot exceed gross wages.\n"
								<< "Re-enter data for employee " << Num << ".\n";
							Val = 0;
						}
		// confirm
						else
						{
							cout << setprecision(2) << fixed
								<< "Wages and taxes for employee " << Num << ":\n"
								<< "  Gross wages: $" << setw(10) << right << Gross << endl
								<< "  State tax:   $" << setw(10) << right << State << endl
								<< "  Federal tax: $" << setw(10) << right << Fed << endl
								<< "  FICA:        $" << setw(10) << right << FICA << endl
								<< "Confirm (Y/N): ";
							cin >> Conf;						
							if ((Conf == 'Y') || (Conf == 'y'))
							{
								Val = 1;
								cout << endl;
							}
							else
							{
								Val = 0;
								cout << "Re-enter data for employee " << Num << ".\n";
							}
						}

					}
					while (Val == 0); // ends do loop for specific data after confirmation of employee number

		// update accumulators
					TotGross += Gross;
					TotState += State;
					TotFed += Fed;
					TotFICA += FICA;
					Val = 0;
				}	
				/* ends if statement that asks for the numbers for a specific employee
				after confirmation of correct employee number
				*/
				
			} // closes the else for the case that employee num is a real employee
		}
		while (Val == 0);
	}
	while (Num != 0);

	cout << "\nPayroll Report\n\n"
		<< setprecision(2) << fixed
		<< "Gross pay total:   $" << setw(12) << right << TotGross << endl
		<< "State tax total:   $" << setw(12) << TotState << endl
		<< "Federal tax total: $" << setw(12) << TotFed << endl
		<< "FICA total:        $" << setw(12) << TotFICA << endl << endl;

	return 0;
}

Just started on chap. 6, which is defining your own functions. I can already see what you guys mean (I think?):

Basically, if (as in the above code) it's too complicated to follow the brackets for various loops, then portions of them need to be broken down into functions that suddenly turn big blocks into single lines that just call your function and thus make everything pretty transparent.

Am I understanding you guys correctly?

As my own exercise, I think I'll try re-writing the above code using some functions.

I'll second the advice to write functions that do one thing and do it well. It makes it easier to debug, maintain, and reuse your code. Also, even though comments help document your code, it's a good idea to regularly ask yourself if it wouldn't be better to make the code more readable by itself. Too many comments are a sign that your code is poorly written.