Checking File Extensions

Hey guys. I am currently trying to write a basic encryption/file viewing program for my linux box, and I have run into a small problem while writing it. I want to check to see if the file I am reading in has a .txt extension on it, so that the program will only take .txt files (insures someone doesn't pass some other non-ASCII file.) I have sort of isolated the problem to the code below, which no matter what I do to it, it seems to only output "Non-text file."

Code:

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

int main(){
	char fn[100]; //String for filename
	char dump[100]; //Temporary extension test
	printf("Please enter a filename...\n> ");
	fgets(fn, sizeof(fn), stdin);
	fn[strlen(fn)-1] = '\0'; //Remove last \n
	strcpy(dump, fn); /
	dump[strlen(dump)-4] = '\0'; //Remove last four characters from dump
	strcat(dump,".txt"); //Make last four characters of dump .txt for extension checking.
	if(strcat(dump, fn) == 0){
		printf("Text file.");
	}
	else{
		printf("Non-text file.");
	} 
	return(0);
}

Can someone please tell me what I am doing wrong?

Thanks in advance,
Robert

> if(strcat(dump, fn) == 0)
Maybe strcmp() is the thing you're after.

foo.txt just became foo.txtfoo.txt

Thanks...wow, that was stupid haha...works brilliantly now. Thank you very much.

Maybe you can use strtok() using the . as the item to look for and use the extension token and compare it