/*
* 300154622
* Exercise 02
* Question 4
* Avner Schwartz
*/

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

typedef int BOOL;

#define FALSE 0
#define TRUE 1

char* sqzstr(char* haystack, char* needles);

void main() {
	char* res;
	res = sqzstr("hello world", "l");
	res = sqzstr("", "or");
	printf("%s\n", res);
	free(res);
}

char* sqzstr(char* haystack, char* needles) {
	static int counter = 0;
	static char* res;
	int i, j, writeInd, haystackLen;
	BOOL isNeedleInHaystack;
	writeInd = 0;
	i = 0;

	// increment the local static counter each time sqzstr is called
	counter++;
	// use malloc only if it's the first time sqzstr was called
	if (counter == 1) {
		haystackLen = strlen(haystack);
		res = (char*)malloc(haystackLen * sizeof(char));
		if (res == NULL) {
			exit(1);
		}
	}

	// if the stack argument is NULL or empty and the res pointer isn't NULL
	if ((haystack == NULL || strcmp(haystack, "") == 0) && (res != NULL)) {
		// call the sqzstr function again with the local static string res as haystack argument
		res = sqzstr(res, needles);
	}
	else {
		// as long as we didn't reach the end of haystack
		while (haystack[i] != '\0') {
			j = 0;
			isNeedleInHaystack = FALSE;
			// as long as we didn't reach the end of needles and the current needle isn't in the haystack
			while (needles[j] != '\0' && isNeedleInHaystack == FALSE) {
				if (needles[j] == haystack[i]) {
					isNeedleInHaystack = TRUE;
				}
				j++;
			}
			// if current needle is indeed not found in the haystack, copy it to the res string
			if (isNeedleInHaystack == FALSE) {
				res[writeInd] = haystack[i];
				writeInd++;
			}
			i++;
		}
		res[writeInd] = '\0';
		res = (char*)realloc(res, (writeInd+1) * sizeof(char));
		if (res == NULL) {
			exit(1);
		}
	}
	return res;
}
/*============== PROGRAM TEST RUNS ==============
he wd
Press any key to continue . . .
*/