Thread: Problem with string output...

Ok people.. this is getting aggravated, and, even though I'm sure it's something very stupid, I can't figure out why this string isn't getting printed.
The little piece of code is supposed to go through a string and remove the '/' character as well as the one right before. So if I have: "Free/d" as my sting, I'm supposed to end up with "Fred". Pretty Simple right?

Here's code (it's not much, I just wanted to make sure my idea was working)

Code:

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

int main () {

 	char string[30];
	int i, j;
	char temp[30];

	strcpy (string, "Blee/ssee/d is tt/he man/.\n");
	printf("%s\n", string);

	for (i = j = 29; i >= 0; ) {
		if (string[i] != '/') {
			temp[j] = string[i];
			printf("temp = %c, string = %c\n", temp[j], string[i]);
			i--;
			j--;
		}
		else
			i = i-2;
	}

	printf("%s\n", string);
	printf("%s\n", temp);

return;
}

My problem is when I run that, string is correct, but temp is blank, even though the printf statement in the for loop makes it print the correct stuff!!
Can anyone explain that to me?

I just tried something else, and temp prints by characters, but won't prints by string.
ie: %c works, %s doesn't!

Why are you doing it the hard way? Go from the front of the string to the end. If you don't, you'll end up with a misaligned string. Consider:

Code:

s1 = "hi/!"
s2 = where we put stuff

s2[3] = s1[3] (the '!')
s2[2] = s1[1] (the 'i")
s2[1] = s1[0] (the 'h')
s2[0] = oops, no more s1, so what does it have?

Quzah.

Quzah,

But if I go from the front to the back, I will have "processed" the character that I want to delete.
The '/' is supposed to mean that both itself, and the preceding character will be deleted, not just itself:
ca/at becomes cat

However, that's not really my concern about this piece of code. I don't understand why neither string will print when I call printf!!!!

Mmmmmm

Code:

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

int main()
{
    char string[30];
    int i, j;

    strcpy(string, "Blee/ssee/d is tt/he man/.\n");
    printf("%s\n", string);
    for ( i = 0, j = 0 ; string[i] ; i++ ) {
        if ( string[i] == '/' ) j--;
        else string[j++] = string[i];
    }
    string[j] = '\0';
    printf("%s\n", string);
    return 0;
}

Since you know the string can never get any longer, an in-place change is easiest to do

Thank you Salem!!
I actually works... )

So, my porblem is fixed.
But I still don't understand why the printf gave me a blank line before (??)
-----------
I found a littel flaw in this code Salem. If anything is in fact deleted from the string, the end of it remains. I couldn't understand why I had an ouput like that:

Blessed is the man.
man.

I just added

Code:

while (string[j]) {
	string[j] = ' ';
	j++;
}

after what you had written

Originally posted by Lau
But I still don't understand why the printf gave me a blank line before (??)

It's because you started at the end of the string, loading the temp buffer from the end. When loaded, the string was shorter than the original leaving you with nulls at the beginning of temp. So temp[0] was equal to '\0' which makes temp an empty string.

Go it Walt!!
Thanks