Separating parallel arrays from txt file - c++

Question

I'm a very novice programmer, and I'm trying to make a program that reads a txt file containing the names of 5 students (first names only) as well as four exam scores for each student. I'm trying to read the names into an array called students, then read the scores into 4 separate arrays named test1, test2, test3, test4, then display it from the monitor. The file looks like this:
Steve 78 65 82 73
Shawn 87 90 79 82
Annie 92 90 89 96
Carol 72 65 65 60
Kathy 34 50 45 20
I'm having a very hard time with breaking up the arrays and organizing them. Can someone help me? Please keep in mind I'm very novice, so I don't know a large amount about programming.
This is my code thus far:
#include <cstdlib>
#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
#include <ctime>
#define over2 "\t\t"
#define over3 "\t\t\t"
#define over4 "\t\t\t\t"
#define down5 "\n\n\n\n\n"
using namespace std;
int main(int argc, char *argv[])
{
ifstream inputFile;
//Constant for max string size
const int SIZE = 5;
//Constant for the scores
string names[SIZE], fileName, line, test1[SIZE], test2[SIZE], test3[SIZE], test4[SIZE];
//input section, user enters their file name
cout << down5 << down5 << over2 << "Please enter your file name: ";
cin >> fileName;
system("CLS");
//open the file containing the responses
inputFile.open(fileName.c_str());
cout << endl;
//kicks you out if file isn't found
if (inputFile)
{
for(int i = 0; i < SIZE; i++)
{
getline(inputFile, line);
names[i] = line;
getline(inputFile, line);
test1[i] = line;
getline(inputFile, line);
test2[i] = line;
getline(inputFile, line);
test3[i] = line;
getline(inputFile, line);
test4[i] = line;
}
inputFile.close();
}
cout << down5 << over3 << "Student\tTest1\tTest2\tTest3\tTest4\n";
cout << over3 << "-------\t-----\t-----\t-----\t-----\n";
for(int i = 0; i < SIZE; i++)
{
cout << over3 << names[i] << endl;
cout << over3 << test1[i] << endl;
cout << over3 << test2[i] << endl;
cout << over3 << test3[i] << endl;
cout << over3 << test4[i] << endl;
}
return 0;
}

Answer 1

Let's look at the structure of the file you're trying to read:
Steve 78 65 82 73
Shawn 87 90 79 82
Annie 92 90 89 96
Carol 72 65 65 60
Kathy 34 50 45 20
The format of the data can be described as follows:
Each line represents a single "record".
Each "record" contains multiple columns.
Columns are separated by whitespace.
You're currently using getline() for every column:
for(int i = 0; i < SIZE; i++)
{
getline(inputFile, line);
names[i] = line;
getline(inputFile, line);
test1[i] = line;
getline(inputFile, line);
test2[i] = line;
getline(inputFile, line);
test3[i] = line;
getline(inputFile, line);
test4[i] = line;
}
...whereas you actually want to read in a single line for each record and split it up:
for (int i = 0; i < SIZE; i++)
{
string line;
size_t start = 0;
// For each line, attempt to read 5 columns:
getline(inputFile, line);
names[i] = get_column(line, start);
test1[i] = get_column(line, start);
test2[i] = get_column(line, start);
test3[i] = get_column(line, start);
test4[i] = get_column(line, start);
}
Here's a modified version of your original code, which splits up each line as described above:
#include <cctype>
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
static string get_column(string line, size_t &pos)
{
size_t len = 0;
// Skip any leading whitespace characters.
while (isspace(line.c_str()[pos])) { ++pos; }
// Count the number of non-whitespace characters that follow.
while (!isspace(line.c_str()[pos+len]) && line.c_str()[pos+len]) { ++len; }
// Extract those characters as a new string.
string result = line.substr(pos, len);
// Update the "start" position (for the next time this function is called).
pos += len;
// Return the string.
return result;
}
int main()
{
const int SIZE = 5;
string names[SIZE], test1[SIZE], test2[SIZE], test3[SIZE], test4[SIZE];
// Ask the user to enter a file name.
cout << "Please enter your file name: ";
string fileName;
cin >> fileName;
// Open the file and read the data.
ifstream inputFile(fileName.c_str());
if (!inputFile.is_open()) { return 0; }
for (int i = 0; i < SIZE; i++)
{
string line;
size_t start = 0;
// For each line, attempt to read 5 columns:
getline(inputFile, line);
names[i] = get_column(line, start);
test1[i] = get_column(line, start);
test2[i] = get_column(line, start);
test3[i] = get_column(line, start);
test4[i] = get_column(line, start);
}
inputFile.close();
// Display the data.
cout << "Student\tTest1\tTest2\tTest3\tTest4" << endl;
cout << "-------\t-----\t-----\t-----\t-----" << endl;
for(int i = 0; i < SIZE; i++)
{
cout << names[i] << "\t";
cout << test1[i] << "\t";
cout << test2[i] << "\t";
cout << test3[i] << "\t";
cout << test4[i] << endl;
}
}
Running the program produces the following output:
Please enter your file name: textfile.txt
Student Test1 Test2 Test3 Test4
------- ----- ----- ----- -----
Steve 78 65 82 73
Shawn 87 90 79 82
Annie 92 90 89 96
Carol 72 65 65 60
Kathy 34 50 45 20
Note that the get_column() function handles multiple spaces or too-short lines, so that this file:
Steve 78 65 82 73
Shawn 87 90
Annie 92 90 89 96
Carol 72
Kathy 34 50 45 20
...produces the following output:
Please enter your file name: textfile.txt
Student Test1 Test2 Test3 Test4
------- ----- ----- ----- -----
Steve 78 65 82 73
Shawn 87 90
Annie 92 90 89 96
Carol 72
Kathy 34 50 45 20

Answer 2

The previous answer is overthinking the problem.
You can use your input file stream to retrieve 'formatted input' (that is, input you know to be in a format such as 'string' then 'int', 'int', 'int', 'int') with the >> operator.
string name;
int score[4];
ifstream mf;
mf.open("score.txt");
// Get name string.
mf >> name;
// Get four score values into an array.
mf >> score[0] >> score[1] >> score[2] >> score[3];
And then:
cout << name;
cout << score[0];
cout << score[1];
cout << score[2];
cout << score[3];