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Program to delete a line given the line number from a file

Last Updated : 20 Feb, 2018
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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 :

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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;"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')
        // file content not to be deleted
        if (line_no != n)
            ofs << c;
    // closing output file
    // closing input file
    // remove the original file
    // 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 

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