brackets.c

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

#define OPEN_BRACKETS 5
#define STR_LENGTH 10

void gen(int length, int opened, int closed, char* str) {
	if (opened + closed == 2 * length) {
		printf("%s\n", str);
		return;
	}

	if (opened < length) {
		char new_str_a[STR_LENGTH];
		strcpy(new_str_a, str); 
		strcat(new_str_a, "(");
		gen(length, opened + 1, closed, new_str_a);
	}

	if (opened > closed) {
		char new_str_b[STR_LENGTH];
		strcpy(new_str_b, str); 
		strcat(new_str_b, ")");
		gen(length, opened, closed + 1, new_str_b);
	}
}

int main() {
	char n[STR_LENGTH];

	gen(OPEN_BRACKETS, 0, 0, n);

	return 0;
}