I am writing a program in c++ that allows a user to enter the name of a file they want to open. However, whenever the program tries to open that file, even if the user inputs an existing file name and the file is in the same directory as the program, the file opening will fail. Why is this happening and how do I address this? I am using MacOS and writing this program in Visual Studio Code and compiling using Xcode's command line tools. The file I am trying to open is a .txt file. For additional background, I am in my first programming class and this is my first time using I/O streams.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(){
ifstream inStream;
ofstream outstream;
string filename1;
//accepting user input of file name
cout << "Enter the file name: ";
cin >> filename1;
//** OPENING FILE **
inStream.open(filename1);
//checking if open fails
if(inStream.fail())
{
cout << "Input file opening failed.\n";
exit(1);
}
return 0;
}
I have also tried writing this code so that the full path of the file is included in the open command, but that doesn't work, either.
Related
Im new to c++ and i was trying to open a ".txt" file using ifstream. the file im using is called "ola.txt" which literally just contains two lines of text without punctuation just plain and simple text. The code that i wrote is this
#include <iostream>
#include <vector>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
int main()
{
int x;
string line;
vector<int> vect;
ifstream inFile("C:\\Users\\ruial\\Desktop\\ola.txt");
inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt");
if (inFile.is_open()) {
while (getline(inFile, line))
{
cout << line << '\n';
}
inFile.close();
}
else {
cout << "Unable to open file";
exit(1); // terminate with error
}
return 0;
}
The path to the file that i wrote is correct such that the file opens, but when the program runs it doesn´t cout the lines that i wrote on the txt file to the cmd, i dont know if this is somewhat important but im coding in visual studio 2019.
I can't seem to find the answer to this problem anywhere in the internet and to be honest i think im doing it right, any help would be much appreciated,thanks in advance.
You are trying to open the inFile twice. First time during inFile construction, ifstream inFile("C:\\Users\\ruial\\Desktop\\ola.txt"), second time you try to open it again with inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt"), when it's already open, which is erroneous, and flags the stream as no longer good.
3 possible fixes:
Remove inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt")
Use default constructor, without specifying the file name
inFile.close() before you open it again (obviously, not the nicest fix).
I'm trying to read each line from a .geom file and save that in a string.
The user shall input the correct (absolute) filepath and then, until now, should get the content of the .geom file printed out on the console.
The problem is that under every circumstance it seems impossible to open the file via my c++ program.
Everytime I check if the file is opened via is_open() it responds with false.
The program, my IDE and the .geom file are all on the same drive and i am currently using windows. The IDE im using is Codeblocks and the executable is build in it.
This is my complete code until now:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
//a function to check if the given file has the .geom extension
bool isGeom(string file){
if(file.substr(file.find_last_of(".") + 1) == "geom") {
return true;
} else {
return false;
}
}
//main func
int main()
{
string filepath, geomInput, line;
cout << "----- GeomView2obj -----" << endl;
cout << "Please enter a valid file path to a .geom file to convert it to an .obj file: \n" << endl;
//get file path by user
getline(cin, filepath);
//declare stream and open file if possible
ifstream geomFile (filepath.c_str());
if(!geomFile.is_open()){
cout << "\nERR: The given file path is invalid or the file does not exist!" << endl;
return 1;
}
if(!isGeom(filepath)){
cout << "\nERR: The given file is not a .geom file!" << endl;
return 1;
}
//read chars from geom file
while(getline(geomFile, line)){
geomInput.append(line + "\n");
}
//print string --- DELETE
cout << geomInput;
geomFile.close();
return 0;
}
I also tried to first declare my ifstream and then opening the file.
I also turned the user input off and entered an absolute path where every folder was seperated with two backslashes \\ instead of one.
I also copied the file to the folder the compiled program lies in and giving the program a relative path to the file as an input, but that also did not help.
Any form of help is much appreciated!
I am using visual studio 2017
I am new to c++ and here I tried to open a txt file, and confirming that it was opened.
#include <iostream>
#include <fstream>
#include <String>
using namespace std;
int main()
{
ifstream infile;
string text;
infile.open("C:\\Users\\gab_a\\source\\repos\\one\\testing.txt");
if (!infile.is_open()) {
cerr << "Specified file could not be found ";
exit(1);
}
else {
cout << "Opened file ";
infile >> text;
cout << text;
}
return 0;
}
it says that it opened it, and it even read the text that was inside the file, but the actual file isn't opening, I even put the file in the same directory as the project. There are also no errors, so why isn't my file opening?
What you're doing is reading the data from the file into a stream. This is not the same as executing a program to open the file. To do that is generally OS specific, but if you're on Windows you can use ShellExecute or CreateProcess. I do suggest you brush up on your C++ a bit - no offense intended
I'm reading in a file name from the keyboard and opening the specified file. However it is not meeting my if statement that determines if it's open or not. Heres my code:
#include "prog.hh"
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
string fileName;
cout << "Enter the file name to be read: ";
cin >> fileName;
ifstream input_file("fileName");
std::string line_; // string which text file contents will be stored in
if(input_file.is_open()){ // validation to see if the file is open
while(getline(input_file, line_)){
std::cout<<line_<< '\n'; //prints the contents of the file into the console
}
input_file.close();
}
else {
std::cout<<"File is not open"<< '\n';
}
std::cin.get();
After being compiled, I type in the file name I want to open and I get back the else message "File is not open", although the ifstream should of opened it. I definitely have the right file I'm trying to open in the correct folder. Any help appreciated, thanks.
change
ifstream input_file("fileName");
to
ifstream input_file(fileName);
Simple program to open up a file and read it's contents. Then a test at the end to see if I did in fact get the information. Every time I run it it tells me that it cannot open the file. I will post the contents of SaleSlips below. Why isn't it opening the file? It is also attempting to delete the file every run as well.
#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;
struct SaleSlip{
char name[20];
int prodID;
double value;
};
void main(){
fstream slips;
SaleSlip sales[17];
slips.open("SaleSlips.txt", ios::in);
if(slips.eof()){
cout << "Cannot open file - SaleSlips.txt"<< endl;
system("pause");
exit(2);
}
int i = 0;
while(!slips.eof()){
slips.getline(sales[i].name, ' ');
slips >> sales[i].prodID;
slips.ignore(5, ' ');
slips >> sales[i].value;
slips.ignore(80, ' ');
i++;
}
cout << sales[1].value;
slips.close();
system("pause");
}
Eric 1 200000.00
Sookie 2 200.00
Sookie 4 200.50
You're opening the stream in output mode by using ios::out. Use ios::in to read from it.
You've got a lot of other issues, too. IE:
-The if(!slips.eof()) after the file open will always cause an exit unless the file is empty.
-In your while loop, you are (probably accidentally) attempting to write the prodID and value into the slips file using <<. Use >> to read from a stream and << to write to it.
You have two problems:
You're opening the file for output (writing)
slips.open("SaleSlips.txt", ios::out);
Useios::in instead for input (reading)
slips.open("SaleSlips.txt", ios::in);
Next, you're immediately testing for !eof(), which is the wrong logic.
if(!slips.eof())
You don't want to be at eof() when opening the file for input. eof() is end of file. When first opening the file for input you want to be at the beginning of the file; being at eof() is a bad thing. Your code should error out if eof() is true, not if it's false:
if(slips.eof()) {
// It's an error if we're starting at eof()
}