20-bit LFSR with a verification function to verify that it does not repeat after the period

lfsr_20bit.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#define MAX_PERIOD 1048575

void generateNums(int *);
void checkDups(int *);
int main(){
	int genNums[MAX_PERIOD];

	generateNums(genNums);
	checkDups(genNums);
	return 0;
}

/*
 * Generate the numbers using LFSR, & puts
 * it into genNums array
 */
void generateNums(int *array){
	int lfsr = 0b01110010011010100011;
	int final = lfsr;
	int mask = 0b11001010000000000000;
	FILE *file = fopen("text", "w+");
	do {
		int unsigned lsb = lfsr & 1; // least significant bit
		lfsr >>=1; //shift right
		/*
		 * toggle masks unneeded if lsb is 0
		 */
		if (lsb == 1)
			lfsr ^= mask; //apply the mask
		*array++ = lfsr;
		fprintf(file, "%d \n", *(array - 1));
	}while (lfsr != final); // runs MAX_PERIOD times
}

void checkDups(int *array){
	for (int i = 0; i < sizeof(array)/sizeof(array[0]); i++){
		// check the sign of array[abs(array[i])]
		if(array[abs(array[i])] > 0){
			// if its positive, make it negative
			array[abs(array[i])] = -array[abs(array[i])];
		} else {
			// we found a repetition
			printf("%d \n", array[i]);
		}
	}
}