Thread: Deleting something on FILE I/O

today i had to write a program that change something in txt but apprently it didnt change it but when i put it to screen it appears that it did so i dunno whats the problem srry for editing alot i had problem with something.

Code:

#include <stdio.h>
#include <string.h>
#include <windows.h>
void changer(char *first,char *exchanger)
{
	int i,x;
	for(i=0,x=0;first[i]=exchanger[x];i++,x++);
}
int main(void)
{
	char buffer[100];
	char exchanger[]="http://www.onemanga.com";
	FILE *fp;
	int i=0;
	fp=fopen("D:\\test\\lol.txt","r+w");
	fp2=fopen("D:\\test\\lchanged.txt","w");
	while(fgets(buffer,sizeof buffer,fp)!=NULL)
	{
		puts(buffer);//for test to see if it changed it or not
		if(strstr(buffer,"http://www.narutocentral.com"))
		{
			changer(buffer,exchanger);
			puts(buffer);//so here it got changed but in txt it didnt !!! so WTF ???
		}
	}
	return 0;
}

Code:

while(fgets(buffer,sizeof buffer,fp)!=NULL)
	{
		puts(buffer);//for test to see if it changed it or not
		if(strstr(buffer,"http://www.narutocentral.com"))
		{
			changer(buffer,exchanger);
			puts(buffer);//so here it got changed but in txt it didnt !!! so WTF ???
		}
	}

I don't see any code here that actually writes to the file...

i thought the changer itself will change it in txt itself ?

yes i want the buffer whish get changed
i also did overwrite and it still didnt work out

Code:

#include <stdio.h>
#include <string.h>
#include <windows.h>
void changer(char *first,char *exchanger)
{
	int i,x;
	for(i=0,x=0;first[i]=exchanger[x];i++,x++);
}
int main(void)
{
	char buffer[100];
	char exchanger[]="http://www.onemanga.com";
	FILE *fp;
	int i=0;
	fp=fopen("D:\\test\\lol.txt","rw");
	while(fgets(buffer,sizeof buffer,fp)!=NULL)
	{
		
		if(strstr(buffer,"http://www.narutocentral.com"))
		{
			changer(buffer,exchanger);
			fprintf(fp,"%s",buffer);
			puts(buffer);
		}
	}
	return 0;
}

Well, I'm not exactly sure what is supposed to be going on here, but I can point out some (possibly) related problems with the code.

Code:

void changer(char *first,char *exchanger)
{
	int i,x;
	for(i=0,x=0;first[i]=exchanger[x];i++,x++);
}

That is an odd for loop, with a very odd conditional statement. I like this:

Code:

char *temp = first;
first = exchanger;
exchanger = first;

Anyways, are you trying to replace every occurance of some text read in from a file with some other text, then output the results to a new file?

im trying to overwrite it in same txt not to another