static_array.c

// sequence implemented as static array
#include <stdlib.h>
#include <stdio.h>

typedef struct s_a static_array;
static_array *new_static_array(int *array, int n);
int length(static_array *s_a);
void iter_sequence(static_array *s_a);
int get_at(static_array *s_a, int i);
void set_at(static_array *s_a, int i, int x);
void insert_at(static_array *s_a, int i, int x);
int delete_at(static_array *s_a, int i);
void insert_first(static_array *s_a, int x);
int delete_first(static_array *s_a);
void insert_last(static_array *s_a, int x);
int delete_last(static_array *s_a);
void resize_array(static_array *s_a);

typedef struct s_a {
	int *sequence;
	int size;
	int length;
} static_array;

static_array* new_static_array(int *array, int n) {
	static_array *s_a;

	s_a = (static_array*) malloc(sizeof(static_array));
	if (s_a == NULL) {
		return NULL;
	}
	
	s_a->sequence = (int*) malloc(sizeof(int) * n);
	if (s_a == NULL) {
		return NULL;
	}

	for (int i = 0; i < n; i++) { 
		s_a->sequence[i] = array[i];
	}
	s_a->length = s_a->size = n;

	return s_a;
}

int get_at(static_array *s_a, int i) {
	if (i >= 0 && i < s_a->length) {
		return s_a->sequence[i];
	}
}

void set_at(static_array *s_a, int i, int x) {
	if (i >= 0 && i < s_a->length) {
		s_a->sequence[i] = x;
	}
}

// insert an element in i-th position
// if array is full then resize
void insert_at(static_array *s_a, int i, int x) {
	if (i >= 0 && i <= s_a->length) {
		int curr;

		if (s_a->length == s_a->size) {
			resize_array(s_a);
		}
		
		curr = s_a->length;
		while (curr > i) {
			s_a->sequence[curr] = s_a->sequence[curr - 1]; // shift rigth
			curr--;
		}
		s_a->sequence[curr] = x;
		s_a->length++;
	}
}

// delete an element in i-th position
int delete_at(static_array *s_a, int i) {
	if (i >= 0 && i < s_a->length) {
		int ret;

		ret = s_a->sequence[i];
		while (i < s_a->length - 1) {
			s_a->sequence[i] = s_a->sequence[i + 1]; // shift left
			i++;
		}
		s_a->length--;

		return ret;
	}
}

void insert_first(static_array *s_a, int x) {
	insert_at(s_a, 0, x);
}

int delete_first(static_array *s_a) {
	return delete_at(s_a, 0);
}

void insert_last(static_array *s_a, int x) {
	insert_at(s_a, s_a->length, x);
}

int delete_last(static_array *s_a) {
	return delete_at(s_a, s_a->length - 1);
}

int length(static_array *s_a) {
	return s_a->length;
}

// resize static array to n + 1
void resize_array(static_array *s_a) {
	int *new_array;

	new_array = (int*) malloc(sizeof(int) * (s_a->size + 1));
	if (new_array == NULL) {
		return;
	}

	for (int i = 0; i < s_a->length; i++) {
		new_array[i] = s_a->sequence[i];
	}

	free(s_a->sequence);
	s_a->sequence = new_array;
	s_a->size++;
}

void iter_sequence(static_array *s_a) {
	for (int i = 0; i < s_a->length; i++) {
		printf("%d ", s_a->sequence[i]);
	}
	printf("\n");
}