Min/max Logic and file read error - c++

Question

Reading from file and Min/max logic.
As more info comes in, I will update my question, statements, and code every 30 minutes so I don't edit faster than some can answer.
My question is, how do I set the program to read one name at a time and not concatenate the names?
The file is a .txt file, and reads:
Jackie Sam Tom Bill Mary Paul Zev Barb John
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
// File stream objects
ifstream inputFile;
inputFile.open("LineUp.txt");
// Non-user variables
string first_In_Line = "",
last_In_Line = "",
previous_Name = "",
next_name = "";
if (inputFile)
{
// Display message to user
cout << "Reading file... \n";
while (inputFile >> next_name)
{
cout << next_name;
if (next_name > last_In_Line)
{
first_In_Line = last_In_Line;
last_In_Line = next_name;
}
else if (next_name < first_In_Line)
{
last_In_Line = first_In_Line;
first_In_Line = next_name;
}
// This else clause should only apply to the first iteration
else
{
first_In_Line = next_name;
}
}
//Close the file
inputFile.close();
// Display first in line and last in line
cout << first_In_Line << " is first in line." << endl;
cout << "And " << last_In_Line << " is last in line." << endl;
}
else
{
// Display error message.
cout << "Error opening the file.\n";
}
return 0;
}
Output is:
Reading file...
JackieSamTomBillMaryPaulZevBarbJohnJohn is first in line.
And Sam is last in line.

Answer 1

What I am proposing to you is to use array then use the algorithm sort function
Array is a data structure which is use to save data while the program is running.
Therefore we could save those data from the file to that array. the name of the array is dataFromFile that could save up to 9 string values. so if you have more names in your file just update the size of the array or use vector
ifstream file("dataToRead.txt");
string dataFromFile[9];
string line;
int index = 0;
if(!file)
{
cout<<"cannot find this file" <<endl;
}
else
{
if(file.is_open())
{
while (getline(file,line))
{
dataFromFile[index] = line;
index++;
}
file.close();
}
}
Then display what we have inside of the array using a loop
for(int j=0;j<9;j++)
{
// to do display
cout<<dataFromFile[j] <<endl;
}
NOW to sort them just #include <algorithm> then use the sort method on the array which is called dataFromFile
sort(begin(dataFromFile),end(dataFromFile));
Then redisplayed what you have into the array
for(int j= 0 ;j < 9;j++)
{
// after sorting
cout<<dataFromFile[j] <<endl;
}

Answer 2

Without using arrays, which is the best solution, there was a logic error in if-statements.
First, strings were initialized as empty, so empty strings were always sorted as first_In_Line. first_In_Line needed assigned a value on the first iteration of the while-loop.
Next, by the fourth iteration of the while loop, the variables became illogically assigned, and "Sam" was passed back and forth between first_In_Line and last_In_Line through the rest of the while-loop.
Here's how I solved this problem:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
// File stream objects
ifstream inputFile;
inputFile.open("LineUp.txt");
// Non-user variables
string first_In_Line = "",
last_In_Line = "",
next_name = "";
if (inputFile)
{
// Display message to user
cout << "Reading file... \n\n";
while (inputFile >> next_name)
{
cout << next_name << endl; // list the names
if (last_In_Line == first_In_Line)
{
first_In_Line = next_name;
}
else if (next_name > last_In_Line)
{
last_In_Line = next_name;
}
else if (next_name < first_In_Line)
{
first_In_Line = next_name;
}
}
//Close the file
inputFile.close();
// Display first in line and last in line
cout << endl << first_In_Line << " is first in line." << endl;
cout << "And " << last_In_Line << " is last in line." << endl;
}
else
{
// Display error message.
cout << "Error opening the file.\n";
}
return 0;
}