Baseball Batting Average Program - c++

Question

I need help with a program for school. We had to write a program that asks the user for information about a baseball player. We need to calculate the players batting average with their games played, number of times at bat and number of hits. I am running into an issue where my computation for the average is outputting a set number and not performing any computations. I am entering whole integers for all the variables that are used for calculation. So i would input numbers like 1, 4 , 10 etc... As the program stands the value my formula is setting itself equal to is 15903.876. All of my variables used for the average formula are declared as integers and the batting average itself is declared as a double. I have done some debugging my self and found that the computation messes up when it divides the number of times at bat by the number of hits. If anyone could help me figure out the issue i would appreciate it.
//libaries
#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>
using namespace std;
class battingAverage
{
public:
string pName;
int nBats;
int tHits;
int gPlayed;
int gcalled;
double average;
double average1;
double playeraverage;
};
int main()
{
string numberPlayers;
int nplayers;
//enters the number of players the user wants to enter data for
cout << "Enter the number of players you want to enter data for: ";
cin >> numberPlayers;
cout << endl;
//converts the value of numberPlayers to nplayers
istringstream convert(numberPlayers);
//sets integer nplayers equal to the value of the string numberPlayers
if(! (istringstream(numberPlayers) >> nplayers) )
{
nplayers = 0;
}
cout << "This program calculates the batting average of baseball players.\nYou may enter data for " << nplayers << " players." << endl;
battingAverage ba[nplayers];
int index = 0;
//while statement to get data
while(index < nplayers)
{
cout << "Enter the players last name: " << endl;
cin >> ba[index].pName;
cout << "Enter the number of games the player played: " << endl;
cin >> ba[index].gPlayed;
cout << ba[index].gPlayed << endl;
cout << "Enter the number of games the player was called in for: " << endl;
cin >> ba[index].gcalled;
cout << ba[index].gcalled << endl;
cout << "Enter the number of times the player was at bat: " << endl;
cin >> ba[index].nBats;
cout << ba[index].nBats << endl;
cout << "Enter the number of time the player hit: " << endl;
cin >> ba[index].tHits;
cout << ba[index].tHits << endl;
if(ba[index].tHits > ba[index].nBats)
{
cout << "Enter a valid value for the number of times the player hit: ";
cin >> ba[index].tHits;
}
cout << endl;
index++;
}
//rounds average to 3 decimal places
cout << fixed << setprecision( 3 );
//average formula
ba[index].playeraverage = (ba[index].nBats / ba[index].tHits) * (ba[index].gPlayed / ba[index].gcalled);//error
cout << ba[index].playeraverage << endl << endl;//just temp line to check calculation of average.
ba[index].average = .000;
ba[index].average1 = .099;
while(ba[index].average < 1 && ba[index].average1 < .899)
{
ba[index].average +=.100;
ba[index].average1 += .1;
//prints chart
cout << setprecision( 1 ) << ba[index].average << "00" << setprecision( 3 ) << setw(12) << ba[index].average1 << endl;
}
cout << "1.000" << setw(12) << "1.000" << endl;
//version of system pause
cout << "\nPress enter to continue...";
cin.sync();
cin.ignore();
return 0;
}

Answer 1

On this line:
ba[index].playeraverage = (ba[index].nBats / ba[index].tHits) * (ba[index].gPlayed / ba[index].gcalled);//error
You have this expression:
(ba[index].nBats / ba[index].tHits)
Because both nBats and tHits are integers, you're using only integer math.
The answer will be an integer.
For example:
nBats = 10 & tHits = 3, you'd expect the expression to be 3.333.
But it would only be 3
To fix this, I recommend changing to:
((double)ba[index].nBats / ba[index].tHits)
Same thing again with the expression about gPlayed and gcalled.

Answer 2

Your value of index is wrong during the calculations.
I found this as soon as I put your code in a debugger and stepped through it, something you really should have done yourself.
You start with int index = 0;, and increment it as the user puts in each player's data.
At the end of the input-loop, index is now the same as the number of players.
(eg. if you had 5 players, index is now 5, and the player data is stored in ba[0], ba[1], ba[2], ba[3], and ba[4])
Note that at this point ba[5] is NOT valid data. But that is exactly where ba[index] is!
You do all your calculations on ba[index], which is invalid data, and you wonder why you get meaningless results?
I recommend you set index back to 0 before starting your calculations, and make another loop that does the necessary calculations for each player 0...4.