Given a file and a line number n, the task is to delete nth line from the given text file.
Suppose the initial content of myfile.txt is :
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After Deletion of Line 2 the content would be :
GeeksforGeeks GeeksforGeeks IDE GeeksforGeeks Contribute
Approach :
1) Open the source file in input mode and read it character by character.
2) Open another file in output mode and place contents in the file character by character.
3) Rename the other file to the source file.
// C++ Program to delete the given // line number from a file #include <bits/stdc++.h> using namespace std;
// Delete n-th line from given file void delete_line( const char *file_name, int n)
{ // open file in read mode or in mode
ifstream is(file_name);
// open file in write mode or out mode
ofstream ofs;
ofs.open( "temp.txt" , ofstream::out);
// loop getting single characters
char c;
int line_no = 1;
while (is.get(c))
{
// if a newline character
if (c == '\n' )
line_no++;
// file content not to be deleted
if (line_no != n)
ofs << c;
}
// closing output file
ofs.close();
// closing input file
is.close();
// remove the original file
remove (file_name);
// rename the file
rename ( "temp.txt" , file_name);
} // Driver code int main()
{ int n = 3;
delete_line( "a.txt" , n);
return 0;
} |
Note: Run this code offline IDE keep text file name as "a.txt" in same folder