Loop Skips User Input

[dfurball]

My displayMenu function is stuck in a continuously loop (keeps outputting) after the second iteration when I call the addPlayer function(4 calls it). Any suggestions on what may be causing this? Thanks in advanced :p

I have a file called "playerdata.txt" which reads in the following:
102 Bob 345 76 34
45 Sue 300 78 21
24 David 200 50 12
76 Pam 210 34 44

//Dfurball RPG
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
#include <ctime>
using namespace std;

struct sPlayer
{
	string name;
	int id, gold, health, exp;
};

void getData(ifstream& inp, sPlayer PlayerAr[], int &numPlayers);
void sortData(sPlayer playerAr[], int numPlayers);
int binarySearch(sPlayer playerAr[], int searchid, int numPlayers);
int displayMenu();
void displayReport(sPlayer playerAr[], int numPlayers);
int addNewplayer(sPlayer playerAr[], int numPlayers);
void attack(sPlayer playerAr[], int playerIdx);
void buyHealthpoints(sPlayer playerAr[], int playerIdx);
int deletePlayer(sPlayer playerAr[], int playerIdx, int numPlayers);
void saveData(sPlayer playerAr[], int numPlayers);
int playerSelect(sPlayer playerAr[], int numPlayers);

void main()
{
	sPlayer playerAr[100];
	int menu;
	bool quit = false;
	ifstream inp;
	int playerIdx = 0;
	int numPlayers = 0;
	
	getData(inp, playerAr, numPlayers);	
	playerIdx = playerSelect(playerAr, numPlayers); // current player
	
	while(!quit)
	{
		menu = displayMenu();

		switch(menu)
		{
		case 1: // select player
			playerIdx = playerSelect(playerAr, numPlayers);
			break;
		case 2: // attack
			attack(playerAr, playerIdx);
			break;
		case 3: // buy health
			buyHealthpoints(playerAr, playerIdx);
			break;
		case 4: // add player
			numPlayers = addNewplayer(playerAr, numPlayers);
			break;
		case 5: // delete player
			numPlayers = deletePlayer(playerAr, playerIdx, numPlayers);
			break;
		case 6: // display report
			displayReport(playerAr, numPlayers);
			break;
		case 0: // exit
			quit = true;
			cout << "You have quit" << endl;
			cout << menu;
			break;
		default:
			break;
			cout << "Invalid menu selection" << endl;
		
		} // switch
	} // while
}

void getData(ifstream& inp, sPlayer playerAr[], int &numPlayers)
{
	int i = 0;
	inp.open("playerdata.txt");
	// how do I make it loop until end of file?
	if(inp.is_open())
	{
		inp >> playerAr[i].id;

		while(inp.eof() == false) //stolen from Matt
		{
			//inp.ignore(1, ' '); //stolen from Matt
			inp >> playerAr[i].name;
			inp >> playerAr[i].gold;
			inp >> playerAr[i].health;
			inp >> playerAr[i].exp;
			i++;
			inp >> playerAr[i].id;
			numPlayers++;
		} // end while
		//numPlayers--;
	}
	else
	{
		cout << "File Error: file not found" << endl;
	}
	inp.close(); 
	sortData(playerAr, numPlayers);
}

void sortData(sPlayer playerAr[], int numPlayers)
{
	bool swapped = true;
	int j = 0;
	sPlayer tmp;

		while (swapped) 
		{
			swapped = false;
			j++;

            for (int i = 0; i < numPlayers - j; i++) 
			{
                  if (playerAr[i].id > playerAr[i + 1].id) 
				  {
					tmp = playerAr[i];
					playerAr[i] = playerAr[i + 1];
					playerAr[i + 1] = tmp;
					swapped = true;
                  }
            }
      }
}

int binarySearch(sPlayer playerAr[], int searchid, int numPlayers)
{
	int mid;
	int first = 0;
	int last = numPlayers; 
	bool found = false;

	while(first <= last && !found)
	{
		mid = (first + last) / 2;
		if(playerAr[mid].id == searchid)
		{
			found = true;
		}
		else if (playerAr[mid].id > searchid)
		{
			last = mid - 1;
		}
		else
		{
			first = mid + 1;
		}
	} //while
	if (found)
	{
		return mid; // position of player in array (playerIdx)
	}
	else
	{
		return -1; // id not found
	}
}

int displayMenu()
{
	int answer;

	cout << "1: Select player" << endl;
	cout << "2: Attack" << endl;
	cout << "3: Purchase health" << endl;
	cout << "4: Add player" << endl;
	cout << "5: Delete player" << endl;
	cout << "6: Player report" << endl;
	cout << "0: Exit" << endl;
	cin >> answer;
	
	return answer;
}

void displayReport(sPlayer playerAr[], int numPlayers)
{
	cout << "Player Info" << endl;
	cout << left << setw(10) << "ID" << setw(20) << "Player Name" << setw(20) << "Health points" << setw(20) << "Gold" << setw(20) << "Experience" << endl;
	for (int i = 0; i < numPlayers; i++)
	{
		cout << setw(10) << playerAr[i].id;
		cout << setw(20) << playerAr[i].name;
		cout << setw(20) << playerAr[i].health;
		cout << setw(20) << playerAr[i].gold;
		cout << setw(20) << playerAr[i].exp;
		cout << endl;
	}
}

int addNewplayer(sPlayer playerAr[], int numPlayers)
{
	bool found = false;
	string name;
	int id, gold, hp, exp;
	int bin;
	
	while(found == false)
	{
		cout << "Enter ID: ";
		cin >> id; 
	
		// call binary search
		bin =  binarySearch(playerAr, id, numPlayers);
		if(bin == -1) //ID is not in use therefor create new player
		{
			cout << "Enter player name: " << endl;
			getline(cin, name);
			cin.ignore(1);
			cout << endl;
			// set default values
			gold = 200;
			hp = 50; 
			exp = 0;
			playerAr[numPlayers].id = id;
			playerAr[numPlayers].name = name;
			playerAr[numPlayers].gold = gold;
			playerAr[numPlayers].health = hp;
			playerAr[numPlayers].exp = exp;
			found = true;
			numPlayers++;
			break;
		}
		else
		{
			cout <<"ID is in use." << endl;
			numPlayers--; // player is not created
			break;
		}
		
	} // while
	return numPlayers; //update numPlayers
}

void attack(sPlayer playerAr[], int playerIdx)
{
	srand((unsigned int) time(NULL)); //usigned int prevents data loss warning 
	int roll = rand() % 2;

	if (playerAr[playerIdx].health >= 5)
	{
		if (roll == 0)
		{	
			playerAr[playerIdx].gold = playerAr[playerIdx].gold + 10;
			playerAr[playerIdx].exp = playerAr[playerIdx].exp + 2;
			cout << "Registered hit!" << endl;  
		}
		else if (roll == 1)
		{
			playerAr[playerIdx].health = playerAr[playerIdx].health - 5;
			playerAr[playerIdx].exp = playerAr[playerIdx].exp + 1;
			cout << "You've been hit!" << endl;  
		}
		else if (roll == 2)
		{
			cout << "You missed!" << endl;
		}
	}
}

void buyHealthpoints(sPlayer playerAr[], int playerIdx)
{
	int num; //quantity

	if(playerAr[playerIdx].gold >= 2)
	{
		cout << "A health potion cost 2 gold. How many would you like to purchase?" << endl;
		cout << "Quantity: ";
		cin >> num;
		cout << endl;
		if(num * 2 < playerAr[playerIdx].gold)
		{
			num = num * 2 ; // hp gained
			cout << "You gained: " << num << " health points!" << endl;
			playerAr[playerIdx].health = playerAr[playerIdx].health + num;
			playerAr[playerIdx].gold =  playerAr[playerIdx].gold - num; 
		}
		else 
		{
			cout << "Not enough gold... poor bastard" << endl;
		}
	}
}

int deletePlayer(sPlayer playerAr[], int playerIdx, int numPlayers)
{
	bool found = false;
	char confirm = ' ';
	int idd = 999; 
	int bin = 2;
	
	while(numPlayers > 1 && found == false) //don't delete last player
	{
		cout << "Select ID for deletion: ";\
		cin >> idd;
		
		//call binary search
		bin = binarySearch(playerAr, idd, numPlayers);
		
		if (bin == -1)
		{
			cout << "ID not found! :( " << endl; // continue loop
		}
		else
		{
			found = true; // break loop
		}
		
	} // while
	while (found == true)
	{
		cout << "ID found. Delete info? (y/n): "; 
		cin >> confirm;
		cout << endl;
		if (confirm == 'Y' || confirm == 'y')
		{
			for (int i = bin; i < numPlayers - 1; i++)
			{
				playerAr[i] = playerAr[i + 1]; // copy players to new location
			} // for
			numPlayers--; // update number of players
			found = false; // exit while loop
			break;
		}
		else if (confirm == 'N' || confirm == 'n')
		{
			found = false;
			break; 
		}
	} // while
	return numPlayers; // update players
}

void saveData(sPlayer playerAr[], int numPlayers)
{
	ofstream outp;
	outp.open("playerdata.txt");
	
	for(int i = 0; i < numPlayers; i++)
	{
		outp << playerAr[i].id;
		outp << playerAr[i].name;
		outp << playerAr[i].gold;
		outp << playerAr[i].health;
		outp << playerAr[i].exp;
	}
}

int playerSelect(sPlayer playerAr[], int numPlayers)
{
	int playerIdx = 0;
	int id = -1;
	int bin = 2; 
	displayReport(playerAr, numPlayers);
	cout << endl << endl;
	cout << "Enter a player ID: ";
	cin >> id;

	bin = binarySearch(playerAr, id, numPlayers);

	if(bin == -1)
	{
		cout << "Binary Search function failed =(" << endl;
	}
	else
	{
		playerIdx = bin;
		cout << "Player selected" << endl;
	}

	return playerIdx;
}

[drognisep]

Does it keep spitting out the menu over and over? Or does it ignore user input into addplayer?

[TheIdeasMan]

It looks to me that the menu will continue to be displayed until the user enters 0. If you want it to do something else after adding a player then call the appropriate function from the addplayer function.

Main should always return an int:

int main() {
//your code here

return 0; //if all is well
}

Hope all goes well.

[TheIdeasMan]

Another thing - you can build up the cout in parts - no need to have one big long statement. Try this:

cout << left << setw(10) << "ID" << setw(20) << "Player Name" ;
cout << setw(20) << "Health points" << setw(20) << "Gold" ;
cout << setw(20) << "Experience" << endl;

There is a bit of a rule that code should not exceed 80 chars per line.

[dfurball]

Thanks for the input.

@TheIdeasMan
Why should main always return an int?
I've never heard of do not exceed 80 chars per line. Is this just for readability?

For clarification: the addPlayer function is called, it asks for the player id and name, and then afterwards it spams displayMenu. It should wait for the user to input a menu selection after its displays, but instead it just keeps outputting the menu:

int answer;
cout << "1: Select player" << endl;
cout << "2: Attack" << endl;
cout << "3: Purchase health" << endl;
cout << "4: Add player" << endl;
cout << "5: Delete player" << endl;
cout << "6: Player report" << endl;
cout << "0: Exit" << endl;
cin >> answer;
return answer;

[Chervil]

Why should main always return an int?

Because the operating system may use the returned value to determine success or failure, for example if the prgram is run from within a script.

I've never heard of do not exceed 80 chars per line. Is this just for readability?

Legibility and Printability.

Also, online it is considered poor form for any webpage to require horizontal scrolling. The same might be said during editing of source code. Although individual users may have screens wide enough to accommodate the full width, it is generally accepted that shorter lines are more legible.

That's the reason why newspapers divide the page into columns. Although a headline extending the full page width is easy to read, the same could not be said for the body text.

Actually, you don't need to end the line with a semicolon and begin a new statement. Just add a line-break where convenient, and indent the code so it's clear that it is a continuation of the previous line. Remember the compiler ignores whitespace.

[TheIdeasMan]

Why should main always return an int?

A modern compiler should complain about void main(). You can get away with not explicitly returning an int (the compiler will do it implicitly) but you do need to specify int main()

The reason is the OS makes use of the return value, and if you are writing a script that calls you program, you can test the return value to see if your program behaved as expected, and take action otherwise.

It is good practice to do it the way I mentioned earlier.

I've never heard of do not exceed 80 chars per line. Is this just for readability?

Yes. I am not fond of having to scroll sideways all the time, also if someone needs to print the code on paper, it is easier.

One small thing:
if (confirm == 'Y' || confirm == 'y')

If you make use of std::toupper (include <locale> to use it) you won't need to test the variable twice, because it converts the variable to uppercase.

As for the displaymenu function, I don't know why it does not stop for input. As far as I can see, it breaks out of the switch, then the displaymenu is called again - i don't know it doesn't stop for input.

Sorry, I still haven't answered your original question, at least we have fixed a couple of other things.

Hope all goes well - I am looking forward to the answer as well.

[dfurball]

Thanks for the help guys! I discovered the problem was the cin.ignore that I used in my addPlayer function. It ignores the next character, which happens to be the input for the displayMenu, hence an infinite loop. *facepalm*

if(bin == -1) //ID is not in use therefor create new player
		{
			cout << "Enter player name: " << endl;
			getline(cin, name);
			cin.ignore(1);
			cout << endl;
			// set default values
			gold = 200;
			hp = 50; 
			exp = 0;
			playerAr[numPlayers].id = id;
			playerAr[numPlayers].name = name;
			playerAr[numPlayers].gold = gold;
			playerAr[numPlayers].health = hp;
			playerAr[numPlayers].exp = exp;
			found = true;
			numPlayers++;
			break;
		}

[TheIdeasMan]

Oh good - pleased you have figured it out - did you use the debugger to find the problem?

The debugger is often the best way to discover answers.

Hope all goes well :)

[drognisep]

Lol! What's the actual use for cin.ignore()? Is it a user input formatting thing?