Why I am getting an error in rand() function?

The scanf function requires the address of its variable:

scanf("%d", &guess);
            ^ the addressof operator must be used here.

I assume that the random number is the same value everytime you run the program.

You are not seeding the random number generator properly, I tried this and it seems OK.

# include<stdio.h>
# include<stdlib.h>
# include<time.h>
int main() {
	int number;
	int guess = 0;
	int nguesses = 1;
	time_t t;
	srand((unsigned) time(&t));

	number = rand() % 100;
	printf("The number is %d\n", number);

	do {
		printf("Guess the number between 1 to 100\n");

		scanf("%d", guess);
		if (guess < number) {
			printf("Higher number please!\n");
		}
		else if (guess > number) {
			printf("Lower number please!\n");
		}
		else {
			printf("You guessed it in %d attempts\n", nguesses);
		}
		nguesses++;
	} while (guess != number);
	return 0;
}