Programming Fundamentals/Files/C++
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files.cpp
[edit | edit source]// This program creates a file, adds data to the file, displays the file,
// appends more data to the file, displays the file, and then deletes the file.
// It will not run if the file already exists.
//
// References:
// https://www.mathsisfun.com/temperature-conversion.html
// https://en.wikibooks.org/wiki/C%2B%2B_Programming
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
void create_file(string filename);
void read_file(string filename);
void append_file(string filename);
void delete_file(string filename);
int file_exists(string filename);
int main()
{
string FILENAME = "~file.txt";
if(file_exists(FILENAME))
{
cout << "File already exists." << endl;
}
else
{
create_file(FILENAME);
read_file(FILENAME);
append_file(FILENAME);
read_file(FILENAME);
delete_file(FILENAME);
}
}
void create_file(string filename)
{
fstream file;
float c;
float f;
file.open(filename, fstream::out);
file << "C\tF\n";
for(c = 0; c <= 50; c++)
{
f = c * 9 / 5 + 32;
file << c << "\t" << f << endl;
}
file.close();
}
void read_file(string filename)
{
fstream file;
string line;
file.open(filename, fstream::in);
while (getline(file, line))
{
cout << line << endl;
}
file.close();
cout << endl;
}
void append_file(string filename)
{
fstream file;
float c;
float f;
file.open(filename, fstream::out | fstream::app);
for(c = 51; c <= 100; c++)
{
f = c * 9 / 5 + 32;
file << c << "\t" << f << endl;
}
file.close();
}
void delete_file(string filename)
{
remove(filename.c_str());
}
int file_exists(string filename)
{
FILE *file;
file = fopen (filename.c_str(), "r");
if (file != NULL)
{
fclose (file);
}
return (file != NULL);
}
Try It
[edit | edit source]Copy and paste the code above into one of the following free online development environments or use your own C++ compiler / interpreter / IDE.