Program to delete a line given the line number from a file
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 :
w3wiki w3wiki IDE w3wiki Practice w3wiki Contribute
After Deletion of Line 2 the content would be :
w3wiki w3wiki IDE w3wiki 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
Contact Us