Thread: Writing non-duplicates

I have a file called Junk2.txt which looks like this when opened.
1
2
2
3
4
5
5
5
The file is already sorted from smallest to largest. The program that I have now can write all of the integers in the Junk2.txt file in reverse order, which is the first thing it needs to do, so all I have to do now is display it without the duplicate integers. So what should be displayed is
1
2
3
4
5
Can someone please point me in the right direction. Thanks for any help...It's very much appreciated. Here is the code I have written so far.

Code:

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

int main()
{
	FILE *file;
	char filename[300];

	printf("Give file name:");
	scanf("%s",filename);

	file=fopen(filename,"r");
	if(file==NULL)
	{
		perror(NULL);
		return 1;
	}

	largeToSmall(file);
    fclose(file);
	return 0;
}

largeToSmall(FILE *file)
{
	int count;
	count=fgetc(file);
	
	if(count==EOF) 
		return;
	
	largeToSmall(file);
	putchar(count);
}

you could have to varibles, one for the current character and one for the last. then you would just have to see if they match. or you could but it in a array and scan it.

I think I could weed out the duplicates by using an array, but how could the code be changed so that it places each character into an array?

i just now notcied that your numbers are in order, using a array for it doesnt seem tight now. i tried to do it, but mine wont work right

Code:

int getfile(char *file) {
    FILE *data;
    data = fopen(file, "r");
    
    int current;
    int last;
    
    if(data == NULL) {
        perror(NULL);
        return 1;
    } else {
        while( (current = fgetc(data)) != EOF ) {
            if(current != last)
                putchar(current);
                
            last = current;
        }
    }
    
    fclose(data);
    
    return 0;
}

int main (){
    char filename[256];
    
    printf("Give file name:");
    scanf("%s",filename);
 
    getfile(filename);

    return 0;
}

any one see why?

You have to remember that fgetc() will also receive newline characters as well as numbers

the little things kill me everytime................

heres version 2

Code:

#include <stdio.h>

int getfile(char *file) {
    FILE *data;
    data = fopen(file, "r");
    
    char current[2];
    int last = 0;
    
    if(data == NULL) {
        perror(NULL);
        return 1;
    } else {
        while( (fscanf(data, "%s",  current)) != EOF ) {
                if(current[0] != last) {
                    printf("%c\n", current[0]);
                    last = current[0];
                }
        }
    }
    
    fclose(data);
    
    return 0;
}

int main (){
    char filename[256];
    
    printf("Give file name:");
    scanf("%s",filename);
 
    getfile(filename);

    return 0;
}