How can I modify the code above to accept string as user input and use strcmp to compare with the contents of the text file & then delete that line?
I want to enter a string to compare with the text file, and if that word matches, then I want to delete that line containing that string.
How can I modify the code below, since the code below takes line number as input to delete a specific line.
Thank you.
#include <stdio.h>
int main()
{
FILE *fileptr1, *fileptr2;
char filename[40];
char ch;
int delete_line, temp = 1;
printf("Enter file name: ");
scanf("%s", filename);
//open file in read mode
fileptr1 = fopen(filename, "r");
ch = getc(fileptr1);
while (ch != EOF)
{
printf("%c", ch);
ch = getc(fileptr1);
}
//rewind
rewind(fileptr1);
printf(" \n Enter line number of the line to be deleted:");
scanf("%d", &delete_line);
//open new file in write mode
fileptr2 = fopen("replica.c", "w");
ch = 'A';
while (ch != EOF)
{
ch = getc(fileptr1);
//except the line to be deleted
if (temp != delete_line)
{
//copy all lines in file replica.c
putc(ch, fileptr2);
}
if (ch == '\n')
{
temp++;
}
}
fclose(fileptr1);
fclose(fileptr2);
remove(filename);
//rename the file replica.c to original name
rename("replica.c", filename);
printf("\n The contents of file after being modified are as follows:\n");
fileptr1 = fopen(filename, "r");
ch = getc(fileptr1);
while (ch != EOF)
{
printf("%c", ch);
ch = getc(fileptr1);
}
fclose(fileptr1);
return 0;
}
Example of contents in text file:
hello world up
one two three
User input: hello
Updated contents in text file:
one two three
1 answer
Assuming you're actually looking for a substring of a line in the file and not a word (which would require, as @elgonzo indicated, figuring out how to deal with spacing and word boundaries in general), you should look up information about the function strstr.
But also, strstr wants to accept a string to search in, and you're currently reading your file one character at a time. Make your life easier and read up on fgets too.
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