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Reduce code length?

DevHalo (1)
I've only been learning C++ for about a month now. I am currently rewriting this using functions (just learned it), but I was wondering if there are better ways of doing certain things to make coding easier/faster. My code totals about 500~ lines and I can't fit the whole program in here.

What the program does:
Allows the user to input 4 subjects and a grade for each subject. The program then calculates an average. 

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  int main() 
{

	string msg1, msg2, msg3, msg4, msg5, msg6, error1;
	string subject1, subject2, subject3, subject4, name;
	int grade1 = 0, grade2 = 0, grade3 = 0, grade4 = 0, choiceInt1, choiceInt2;
	unsigned int average = 0;
	char choiceChar1, choiceChar2;
	bool choice1 = true;
	bool choice2 = true;
	const int MAX_STRING_SIZE = 20;
	error1 = "[ERROR: 001]";
	msg1 = "[Invalid Number]";
	msg2 = "[Invalid Answer]";
	msg3 = "[Subject successfully entered]";
	msg4 = "[Subject can not be over 20 characters]";
	msg5 = "[Grade successfully entered]";
	msg6 = "[Grade is not between 0 and 100]";

	cout << "[Average Grade Program 2.0]" << endl;

	while (name.size() == 0)
	{
		cout << "What is your name? ";
		getline(cin, name);

		if ((name.size() < MAX_STRING_SIZE))
		{
			cin.clear();
			cin.sync();
			cin.sync();
		}
		else if ((name.size() > MAX_STRING_SIZE))
		{
			cout << "Your name is too long!" << endl;
			name.clear();
			cin.clear();
			cin.sync();
			cin.sync();
		}
		else
		{
			cout << error1 << endl;
			cin.clear();
			cin.sync();
			cin.sync();
		}
	}
	
	cout << "Hello " + name + "!" << endl
		<< "This program will help you get an average of four subjects." << endl
		<< "To start, please select the first subject you would like to edit." << endl;

	while (choice1 == true)
	{
		cout << "----------------------" << endl 
			<< "1. " + subject1 << endl
			<< "2. " + subject2 << endl
			<< "3. " + subject3 << endl
			<< "4. " + subject4 << endl
			<< "5. I am done" << endl
			<< "----------------------" << endl;
		cin >> choiceInt1;
		cin.sync();
		cin.sync();

		if ((choiceInt1 > 0) && (choiceInt1 < 6) && (cin.good()))
		{
			if (choiceInt1 == 1)
			{
				cout << "My first subject is ";
				getline(cin, subject1);
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((subject1.size() < MAX_STRING_SIZE))
					{
						cout << msg3 << endl;
					}
					else if ((subject1.size() > MAX_STRING_SIZE))
					{
						cout << msg4 << endl;
						subject1.clear();
					}
				}
				else
				{
					cout << error1 << endl;
					subject1.clear();
					cin.clear();
				}
			}
			else if (choiceInt1 == 2)
			{
				cout << "My second subject is ";
				getline(cin, subject2);
				cin.sync();
				cin.sync();
				
				if (cin.good())
				{
					if ((subject2.size() < MAX_STRING_SIZE) && (cin.good()))
					{
						cout << msg3 << endl;
					}
					else if ((subject2.size() > MAX_STRING_SIZE) && (cin.good()))
					{
						cout << msg4 << endl;
						subject2.clear();
					}
				}
				else
				{
					cout << error1 << endl;
					subject2.clear();
					cin.clear();
				}
			}
			else if (choiceInt1 == 3)
			{
				cout << "My third subject is ";
				getline(cin, subject3);
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((subject3.size() < MAX_STRING_SIZE))
					{
						cout << msg3 << endl;
					}
					else if ((subject3.size() > MAX_STRING_SIZE))
					{
						cout << msg4 << endl;
						subject3.clear();
					}
				}
				else
				{
					cout << error1 << endl;
					subject3.clear();
					cin.clear();
				}
			}
			else if (choiceInt1 == 4)
			{
				cout << "My third subject is ";
				getline(cin, subject4);
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((subject4.size() < MAX_STRING_SIZE))
					{
						cout << msg3 << endl;
					}
					else if ((subject4.size() > MAX_STRING_SIZE))
					{
						cout << msg4 << endl;
						subject4.clear();
					}
				}
				else
				{
					cout << error1 << endl;
					subject4.clear();
					cin.clear();
				}
			}
			else if (choiceInt1 == 5)
			{
				cout << "Are you sure these are correct?" << endl;
				cin >> choiceChar1;
				cin.sync();
				cin.sync();

				if ((choiceChar1 != 'Y') || (choiceChar1 != 'y') || (choiceChar1 != 'N') || (choiceChar1 != 'n'))
				{

					if (cin.good())
					{
						if ((choiceChar1 == 'Y') || (choiceChar1 == 'y'))
						{
							choice1 = false;
						}
						else if ((choiceChar1 == 'N') || (choiceChar1 == 'n'))
						{
							continue;
						}
						else
						{
							cout << msg2 << endl;
							cin.clear();
						}
					}
					else
					{
						cout << msg2 << endl;
						cin.clear();
					}
				}
				else
				{
					cout << msg2 << endl;
					cin.clear();
				}
			}
			else
			{
				cout << error1 << endl;
				break;
			}
		}
		else
		{
			cout << msg1 << endl;
			cin.clear();		
		}
	}

	cout << "Please enter in your grades for each subject" << endl;

	while (choice2 == true)
	{
		cout << "----------------------" << endl 
			<< "1. " + subject1 + ": " << grade1 << endl
			<< "2. " + subject2 + ": " << grade2 << endl
			<< "3. " + subject3 + ": " << grade3 << endl
			<< "4. " + subject4 + ": " << grade4 << endl
			<< "5. I am done" << endl
			<< "----------------------" << endl;
		cin >> choiceInt2;
		cin.sync();
		cin.sync();

		if ((choiceInt2 > 0) && (choiceInt2 < 6) && (cin.good()))
		{
			if (choiceInt2 == 1)
			{
				cout << "What grade did you recieve in " + subject1 + "?" << endl;
				cin >> grade1;
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((grade1 > -1) && (grade1 < 101))
					{
						cout << msg5 << endl;
					}
					else
					{
						cout << msg6 << endl;
						grade1 = 0;
					}
				}
				else
				{
					cout << msg1 << endl;
					cin.clear();
					grade1 = 0;
				}
			}
			else if (choiceInt2 == 2)
			{
				cout << "What grade did you recieve in " + subject2 + "?" << endl;
				cin >> grade2;
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((grade2 > -1) && (grade2 < 101))
					{
						cout << msg5 << endl;
					}
					else
					{
						cout << msg6 << endl;
						grade2 = 0;
					}
				}
				else
				{
					cout << msg1 << endl;
					cin.clear();
					grade2 = 0;
				}
			}
			else if (choiceInt2 == 3)
			{
				cout << "What grade did you recieve in " + subject3 + "?" << endl;
				cin >> grade3;
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((grade3 > -1) && (grade3 < 101))
					{
						cout << msg5 << endl;
					}
					else
					{
						cout << msg6 << endl;
						grade3 = 0;
					}
				}
				else
				{
					cout << msg1 << endl;
					cin.clear();
					grade3 = 0;
				}
			}
			else if (choiceInt2 == 4)
			{
				cout << "What grade did you recieve in " + subject4 + "?" << endl;
				cin >> grade4;
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((grade4 > -1) && (grade4 < 101))
					{
						cout << msg5 << endl;
					}
					else
					{
						cout << msg6 << endl;
						grade4 = 0;
					}
				}
				else
				{
					cout << msg1 << endl;
					cin.clear();
					grade4 = 0;
				}
			}
			else if (choiceInt2 == 5)
			{
				cout << "Are you sure these are correct?" << endl;
				cin >> choiceChar2;
				cin.sync();
				cin.sync();

				if (cin.good())
				{
					if ((choiceChar2 == 'Y') || (choiceChar2 == 'y'))
					{
						choice2 = false;
					}
					else if ((choiceChar2 == 'N') || (choiceChar2 == 'n'))
					{
						continue;
					}
					else
					{
						cout << msg2 << endl;
						cin.clear();
					}
				}
				else
				{
					cout << msg2 << endl;
					cin.clear();
				}
			}
			else
			{
				cout << error1 << endl;
				cin.clear();
			}
		}
		else
		{
			cout << msg1 << endl;
			cin.clear();		
		}
	}
Annatar (69)
Replacing a few of your if/else() with switch() could shorten the code, but I believe what you really should be focusing on is repeated lines of code.

I see there are instructions that often come back in different if/else(). You could probably use loops so you would only need to write certain lines once and still get them to apply to different situations. It will involve some rethinking/rewriting though, and it might be tricky at times.

There might be other simpler solutions, but with my basic C++ knowledge that's all I can suggest for now.
Last edited on
Chervil (7320)
I think you should be using arrays to hold the names of each subject and the grades. Also, the code makes liberal use of cin.sync() which unfortunately may not behave consistently from one compiler to another is is probably best avoided. Also cin.clear() is used unnecessarily many times.

Something like this, though in practice I would split this into separate functions, for getting the persons name, the subject names, the grades etc. This is kind of thrown together, and it still needs some tidying up and rework I think.

I used an array for the error messages, but I'm not convinced this is the best approach, as the code is easier to read if it is obvious which message is being output without having to refer to the definition to make sense of it - that's purely an issue of code legibility, not of functionality.
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#include <iostream>
#include <iomanip>
#include <cmath>
#include <string>
#include <limits>

    using namespace std;

void emptyBuffer()
{
    // Empty input buffer
    std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );
}

int main()
{
    string msg[8] = {
        "[ERROR: 001]",
        "[Invalid Number]",
        "[Invalid Answer]",
        "[Subject successfully entered]",
        "[Subject can not be over 20 characters]",
        "[Grade successfully entered]",
        "[Grade is not between 0 and 100]",
        "Invalid Choice"
    };

    string numbers[4] = { "first", "second", "third", "fourth" };

    string name;
    string subject[4];
    int grade[4] = { 0 };

    int  choice;
    char ch;

    const unsigned int MAX_STRING_SIZE = 20;

    cout << "[Average Grade Program 2.0]" << endl;

    bool done = false;
    while (!done)
    {
        cout << "What is your name? ";
        getline(cin, name);

        if ((name.size() <= MAX_STRING_SIZE))
            done = true;
        else
            cout << "Your name is too long!" << endl;
    }

    cout << "Hello " + name + "!\n"
         << "This program will help you get an average of four subjects.\n"
         << "To start, please select the first subject you would like to edit." << endl;

    done = false;
    while (!done)
    {
        cout << "----------------------" << endl
            << "1. " + subject[0] << endl
            << "2. " + subject[1] << endl
            << "3. " + subject[2] << endl
            << "4. " + subject[3] << endl
            << "5. I am done" << endl
            << "----------------------" << endl;

        cin >> choice;

        if (!cin)
        {
            cin.clear();            // reset the error flags
            emptyBuffer();          // empty the input buffer
            cout << msg[1] << endl; // Invalid Number
            continue;
        }
        
        emptyBuffer();          // empty the input buffer
        
        if ((choice >= 1) && (choice <= 4))
        {
            int ix = choice - 1;

            cout << "My " << numbers[ix] << " subject is ";
            getline(cin, subject[ix]);

            if (subject[ix].size() <= MAX_STRING_SIZE)
            {
                cout << msg[3] << endl; // Subject successfully entered
            }
            else
            {
                cout << msg[4] << endl; // Subject can not be over 20 characters
            }
        }
        else if (choice == 5)
        {
            cout << "Are you sure these are correct?" << endl;
            cin >> ch;
            emptyBuffer();              // empty the input buffer

            ch = toupper(ch);

            if (ch == 'Y')
                done = true;
            else if (ch != 'N')
                cout << msg[2] << endl;  // Invalid Answer
        }
        else
        {
            cout << msg[7] << endl;      // Invalid Choice
        }
    }

    cout << "Please enter in your grades for each subject" << endl;

    done = false;
    while (!done)
    {
        cout << "----------------------" << endl
             << "1. " << subject[0] << ": " << grade[0] << endl
             << "2. " << subject[1] << ": " << grade[1] << endl
             << "3. " << subject[2] << ": " << grade[2] << endl
             << "4. " << subject[3] << ": " << grade[3] << endl
             << "5. I am done" << endl
             << "----------------------" << endl;
        cin >> choice;

        if (!cin)
        {
            cin.clear();            // reset the error flags
            emptyBuffer();          // empty the input buffer
            cout << msg[1] << endl; // Invalid Number
            continue;
        }
        
        emptyBuffer();              // empty the input buffer
        
        if ((choice >= 1) && (choice <= 4))
        {
            int ix = choice - 1;

            cout << "What grade did you receive in " + subject[ix] + "?" << endl;
            cin >> grade[ix];
            if (!cin)
            {
                cin.clear();            // reset the error flags
                emptyBuffer();          // empty the input buffer
                cout << msg[1] << endl; // Invalid Number
            }
            else
            {
                if ((grade[ix] >= 0) && (grade[ix] <= 100))
                {
                    cout << msg[5] << endl;  // Grade successfully entered
                }
                else
                {
                    cout << msg[6] << endl;  //  Grade is not between 0 and 100
                    grade[ix] = 0;
                }
            }
        }
        else if (choice == 5)
        {
            cout << "Are you sure these are correct?" << endl;
            cin >> ch;
            emptyBuffer();               // empty the input buffer

            ch = toupper(ch);

            if (ch == 'Y')
                done = true;
            else if (ch != 'N')
                cout << msg[2] << endl;   // Invalid Answer
        }
        else
        {
            cout << msg[7] << endl;      // Invalid Choice
        }        
    }

    return 0;
}

Last edited on
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