These are the contents of my example file:
abcdefg hijk lmnopqrstAB CSTAKLJSKDJD KSA FIND ME akjsdkjhwjkjhasfkajbsdh ADHKJAHSKDJH
I need to find and delete the 'FIND ME' inside of the file so the output would look like this:
abcdefg hijk lmnopqrstAB CSTAKLJSKDJD KSA akjsdkjhwjkjhasfkajbsdh ADHKJAHSKDJH
I have tried the following method of doing getline and then writing all of the contents except the FIND ME into a temporary file and then rename the temporary file back.
string deleteline;
string line;
ifstream fin;
fin.open("example.txt");
ofstream temp;
temp.open("temp.txt");
cout << "Which line do you want to remove? ";
cin >> deleteline;
while (getline(fin,line))
{
if (line != deleteline)
{
temp << line << endl;
}
}
temp.close();
fin.close();
remove("example.txt");
rename("temp.txt","example.txt");
but it doesn't work. Just as a side note: the file has NO newline/linefeeds. So the file contents are all written in 1 line.
EDIT:
FIXED CODE:
while (getline(fin,line))
{
line.replace(line.find(deleteline),deleteline.length(),"");
temp << line << endl;
}
This gets me the results I expected. Thank you everyone for helping!
Step 1 − Read file path and line number to remove at runtime. Step 2 − Open file in read mode and store in source file. Step 3 − Create and open a temporary file in write mode and store its reference in Temporary file. Step 4 − Initialize a count = 1 to track line number.
To delete a line, we'll use the sed “d” command. Note that you have to declare which line to delete. Otherwise, sed will delete all the lines.
In case anyone would like it I have converted Venraey's useful code into a function:
#include <iostream>
#include <fstream>
void eraseFileLine(std::string path, std::string eraseLine) {
std::string line;
std::ifstream fin;
fin.open(path);
// contents of path must be copied to a temp file then
// renamed back to the path file
std::ofstream temp;
temp.open("temp.txt");
while (getline(fin, line)) {
// write all lines to temp other than the line marked for erasing
if (line != eraseLine)
temp << line << std::endl;
}
temp.close();
fin.close();
// required conversion for remove and rename functions
const char * p = path.c_str();
remove(p);
rename("temp.txt", p);
}
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