Entering data from .txt into struct array - c++

Question

For my c++ homework, I have an .txt document containing building information ordered like:
Building name
year built
lat coordinate
lon coordinate
ex.
Parking Deck
1993
34.2252
37.5563
Admin Building
1985
34.2356
37.5734
I have to read this into an array of my created struct:
struct list
{
char name[50];
int yearBuilt;
double latCoord;
double lonCoord;
} building;
now I've created a for loop to read in the data to my created array of type list:
list buildingnumber[SIZE]; //array for buildings
But when I try to print out the "k" earliest buildings made, it shows no data in the array
Here's my current code:
#include <iostream>
#include <fstream>
#include <istream>
#include <cstdlib>
#include <string>
using namespace std;
const int SIZE = 5000;
//struct for building type
struct list
{
char name[50];
int yearBuilt;
double latCoord;
double lonCoord;
}building;
list buildingnumber[SIZE]; //array for buildings
void InsertionSort(list buildingnumber[], int buildingsloaded)
{
int key = 0, i = 0;
for(int j = 1; j < buildingsloaded; j++)
{
key=buildingnumber[j].yearBuilt;
i=j-1;
while(buildingnumber[i].yearBuilt > key && i >= 0)
{
buildingnumber[i+1] = buildingnumber[i];
i--;
}
buildingnumber[i+1].yearBuilt = key;
}
}
int main()
{
char filePath[50];
ifstream openFile;
cout << "Enter the path of the building file: ";
cin.getline(filePath, 50);
openFile.open(filePath);
//verify if file is opened + report buildings loaded
int buildingsloaded = 0;
if(!openFile.fail())
{
while(openFile >> building.name >> building.yearBuilt >> building.latCoord >> building.lonCoord)
{
buildingsloaded++;
}
cout << buildingsloaded << " buildings have been loaded." << endl;
}
// get how many buildings user wants
int k = 0;
cout << "How many buildings are you interested in?: ";
cin >> k;
//create array
// loadKbuildings(building, buildingsloaded);
for(int i = 0; i < k; i++)
{
openFile >> buildingnumber[i].name >> buildingnumber[i].yearBuilt >> buildingnumber[i].latCoord >> buildingnumber[i].lonCoord;
}
// insertion sort
InsertionSort(buildingnumber, buildingsloaded);
// display earliest k buildings
cout << "The " << k << " oldest buildings are: " << endl;
int i = 0;
while ( i < k )
{
cout << buildingnumber[i].name << endl;
cout << "Year Built: " << buildingnumber[i].yearBuilt << endl;
cout << "Coordinates: (" << buildingnumber[i].latCoord << "," << buildingnumber[i].lonCoord << ")" << endl;
cout << endl;
i++;
}
}

Answer 1

The problem is here:
if(!openFile.fail())
{
while(openFile >> building.name >> building.yearBuilt >> building.latCoord >> building.lonCoord)
{
buildingsloaded++;
}
cout << buildingsloaded << " buildings have been loaded." << endl;
}
You've read all of the data already (to count the number of buildings); the next time you try to grab the data, it's gone.
You can resolve this issue by storing the buildings in an array the first scan through.
int c = 0;
if(!openFile.fail())
{
// *
while(openFile >> buildingnumber[c].name >> buildingnumber[c].yearBuilt >> buildingnumber[c].latCoord >> buildingnumber[c].lonCoord)
{
buildingsloaded++;
c++;
}
cout << buildingsloaded << " buildings have been loaded." << endl;
}
As per WhozCraig's comment, the line under the star only reads in one word for the building's name; you should use cin.getline() instead and change around the loop condition.
You should obviously also take out the data reading section below:
//create array
// loadKbuildings(building, buildingsloaded);
for(int i = 0; i < k; i++)
{
openFile >> buildingnumber[i].name >> buildingnumber[i].yearBuilt >> buildingnumber[i].latCoord >> buildingnumber[i].lonCoord;
}