Reading file to Vector
Hello, im having trouble reading the text file to vector. And writing what is read into another file. Can someone help. Thanks.
As of now, it only reads the first line and print that 1st line to output file.
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#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
int main()
{
const int SIZE = 25;
ifstream dataFile;
ofstream outFile;
string line;
vector<string> quiz(SIZE);
dataFile.open("QuestionBank.txt");
if (!dataFile) //if else statment to display error message for corrupted inout file, if no error proceed.
cout << "Error opening data file\n";
else
{
for (int i = 0; i < SIZE; i++)
{
getline(dataFile, line);
quiz.push_back(line);
outFile.open("stats.txt"); //Print gathered max, min and avg. values to a sperate new file called, stats.txt
outFile << line << endl; // Comments displayed in file.
}
dataFile.close();
}
cout << endl;
cout << "Welcome to Program \n";
cout << "------------------------\n";
cout << endl;
system("pause");
return 0;
}
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Last edited on
Better use getline like this, so you don't leave out data inside your files. It will ensure that all strings will be pushed onto the vector.
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std::string line;
while(std::getline(file, line, ' ')
quiz.push_back(line);
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Like this?
But if i do this, i get an error. Red sguilly lines appear under quiz.
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if (!dataFile) //if else statment to display error message for corrupted inout file, if no error proceed.
cout << "Error opening data file\n";
else
{
//for (int i = 0; i < SIZE; i++)
//{
// getline(dataFile, line);
// quiz.push_back(line);
// outFile.open("Answers.txt");
// outFile << "NEW : " << line << endl; // Comments displayed in file.
//}
while (getline(dataFile, line, ' ')
quiz.push_back(line);
dataFile.close();
}
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Last edited on
Ok, so i've figured out the error.
But this only prints the 1st line.
There are over 10 lines in the file.
In your first post you were opening stats.txt INSIDE the for loop - I.e repeatedly. It needs to be before that loop.
Like this?
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else
{
for (unsigned int i = 0; i < quiz.size(); i++)
{
/*getline(dataFile, line);
quiz.push_back(line);*/
while (getline(dataFile, line))
quiz.push_back(line);
}
outFile.open("Answers.txt");
outFile << "Hello : " << line << endl;
dataFile.close();
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Split your program up into separate functions to make it easier to read.
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vector<string> read_file( const string& filename )
{
ifstream ifs{ filename };
// throw when ifs.bad( ), indicates something catastrophic
ifs.exception( ifs.exception( ) | ios_base::badbit )
// #include <exception>
if( !ifs ) throw exception{ "can't open " + filename };
string line{}, vector<string> quiz{};
while( getline( ifs, line ) ) {
// read the whole file
if( ifs.eof( ) ) return quiz;
if( ifs.fail( ) )
throw exception{ "failed to read " + filename };
quiz.push_back( line );
}
if( ifs.fail( ) )
throw exception{ "failed to read " + filename };
}
void keep_window_open( )
{
cout << "Enter a character to exit ";
char c{};
cin >> c;
}
int main( )
{
try {
const string filename{ "QuestionBank.txt" };
vector<string> quiz{ read_file( filename ) };
}
catch( const exception& e ) {
cout << "exception caught: " << e.what( ) << '\n';
keep_window_open( );
}
catch( ... ) {
cout << "unhandled exception caught\n";
keep_window_open( );
}
keep_window_open( );
}
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Last edited on
Well yes, OK. As long as you don't keep trying to open the file within a loop.
Can you show us the latest version of your code (in full) and state the latest version of what is wrong with it (if you haven't fixed it already).
Thank you. i figured it out. It was the loop. Thank you.
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