Thread: for loop question

Yes,

This may sound like the rest, but this actually has to do with something different. I'm not quite understanding why im running into the problem. Firstly, here is the code:

Code:

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

void removeLetters(char *str, int n);

int main() {
	char str[64] = {"We Remove First And Last Three Letters Now"};

	removeLetters(str, 3);

	printf("%s\n", str);

	return 0;
}

void removeLetters(char *str, int n) {
	int i, len, pos = 0;

	len = strlen(str);

	// Go through loop starting at 'n'
	for (i = n; i < len && pos != len-n*2; i++, pos++) {
		str[pos] = str[i];
		str[pos++] = '\0';
	}
}

Next, this is not homework, I have done this code inside out a billion times, but this time it hasn't worked. Though my second favorite way to do this is:

Code:

void removeLetters(char *str, int n) {
	memcpy(str, &str[n], strlen(str));
	str[strlen( str )-n] = 0x00;
}

Though I am trying a different approach. My problem so far is that "pos" never increments in my for loop statement but if I put pos++ inside the statement, not the call it works fine. Example:

Code:

for (i = n; i < len && pos != len-n*2; i++) {
	str[pos] = str[i];
	pos++;
	str[pos] = '\0';
}

To clarify what I want to do is trim off the first 3 and the last three letters of my sentence. I just dont like having to do at the end the whole "str[strlen(str)-n]" thing. That's why I have tried to write another way.

Is there a simple explanation why "pos" won't increment in my for loop call?


Thank you for your time,
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Alright,

A smoother approach:

Code:

void removeLetters(char *str, int n) {
	int i, len, pos = 0;

	len = n*2 > (int)strlen(str) ? n : strlen(str);

	// Go through loop starting at 'n'
	for (i = n; i < len && pos != len-n*2; i++) {
		str[pos++] = str[i];
	}

	str[pos] = '\0';
}

Is that more reasonable?

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Thanks for the help,

I just wasnt to sure if my implementation was concise. My code now runs beautifully without memcpy worries, etc... Thanks once again!

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