Question

How to remove lines from a text file that start with square brackets ([) in C

Answer 1

#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void removeLinesStartWith(char ch, char file[]) {
    char filetmp[32] = "tmp.txt";
    FILE* fp = fopen(file, "r");
    FILE* fptmp = fopen(filetmp, "w");

    if (fp == NULL || fptmp == NULL) {
        printf("Error open file\n");
        exit(EXIT_FAILURE);
    }

    char s[128];
    int i = 1;
    while ((fgets(s, 128, fp)) != NULL) {
        if (s[0] != ch)
            fputs(s, fptmp);
        i++;
    }

    fclose(fp);
    fclose(fptmp);

    remove(file);
    rename(filetmp, file);
}

void readFile(char file[]) {
    FILE* fp = fopen(file, "r");

    char ch;
    while ((ch = fgetc(fp)) != EOF)
        putchar(ch);

    fclose(fp);
}

int main()
{
    char file[100] = "d:\\data.txt";

    readFile(file);

    removeLinesStartWith('[', file);

    puts("\n--------------");

    readFile(file);

    return 0;
}



/*
run:

/*
run:

c c++ c#
[abc]
java python
[xyz]
javascript php
--------------
c c++ c#
java python
javascript php

*/

 

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