Thread: file I/O

I am trying to write the content of a document that the user specify into a new file which has teh same name but with teh extension .new

How can i do that? I have marked <======= to show where the problem is.

Code:

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

FILE *ofp;
FILE *ifp;

int main(int argc, char*argv[])
{
	int ch;
	char *document;

	if (argc==2)
        {
		document=malloc(strlen(argv[1]));
	    strcpy (document, argv[1]);
		}
	else {perror("date2");exit(1);}
	
	ifp=fopen(document,"r");
	ofp=fopen(document.new,"w");     <=========
	
	if(ifp!='\0')
	{
		while ((ch=fgetc(ifp))!=EOF)
		{		       
		fputc(ch,ofp);
		}		
	}
	else {printf("\nError Opening File.\n");}

	free(document);
	fclose(ifp);
	fclose(ofp);

	return 0;
}

Thanks Salem....

How do I put the \0 at the end of the string....(I can never get it!!!!) and I thought c does it automatically

Yes you are right I want to change any file that the user uses into .new and not file .txt.new....

Iam going to work on it now.....

OK I have reached a dead end.....

How can I change what the file extention that teh use typed at the comand prompt.

ex: if typed output.txt, I want my programto create output.new
currently my program does this: output.txt.new which is not what I want.


I am also trying to insert in teh output file letters:
The input file has numbers like that:
12
13
14
15

I want to create an output file with extension .new that assign a letter after each 2 number lines
like that:
12 a
13 b
14
15
16 a
17 b
...

Code:

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

FILE *ofp;
FILE *ifp;

int main(int argc, char*argv[])
{
	int ch;
	char *document;

	if (argc==2)
        {
		document=malloc(strlen(argv[1]) + sizeof(".new")+1);
	    strcpy (document, argv[1]);
		}
	else {perror("date2");exit(1);}
	
	ifp=fopen(document,"r");
	strcat(document, ".new");
	ofp=fopen(document,"w");
	
	if(ifp!='\0')
	{
		while ((ch=fgetc(ifp))!=EOF)
		{		       
			fputc(ch,ofp);
			fseek(ofp,7,SEEK_SET);
		                    fprintf(ofp,"here");
		}		
	}
	else {fprintf(stderr,"date2:Error Opening File.\n"); exit(1);}

	free(document);
	fclose(ifp);
	fclose(ofp);

	return 0;
}

I am trying to insert into the output file letters:

The input file has numbers like that:
12
13
14
15

I want to create an output file with extension .new (which I did!)that assign a letter after each 2 number lines
like that:
12 a
13 b
14
15
16 a
17 b
...

Need help....Thanks

Here is my latest code

Code:

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

FILE *ofp;
FILE *ifp;

int main(int argc, char*argv[])
{
	int k;
	char fileline[50];
	char *document;
	char *p;

	if (argc==2)
        {
		document=malloc(strlen(argv[1]) + sizeof(".new")+1);
	    strcpy (document, argv[1]);
		}
	else {perror("date2");exit(1);}
	
	ifp=fopen(document,"r");
	
	p = strrchr(document,'.');
	if (p !=NULL ) *p = '\0';
	strcat(document, ".new");

	ofp=fopen(document,"w");		
	
            fgets(fileline,sizeof(fileline),ifp);
           	fputs(fileline,ofp);
			fseek(ofp,4,SEEK_SET);
			fprintf(ofp,"a");

			rewind(ifp);
			fseek(ifp,2,SEEK_SET);
			fgets(fileline,sizeof(fileline),ifp);
          	fputs(fileline,ofp);
			//fseek(ofp,4,SEEK_SET);
			//fprintf(ofp,"b");

		
	free(document);
	fclose(ifp);
	fclose(ofp);

	return 0;
}