C Language Array Add Delete Navigation Question.

#include <stdio.h>
#include <stdlib.h>
#define MAX_LIST_SIZE 100000

typedef int Element;
Element data[MAX_LIST_SIZE];
int length = 0;

void error(char *str)
{
    fprintf(stderr, "%s\n", str);
    exit(1);
};

void init_list()                 {length = 0; }
void clear_list()                {length = 0; }
int is_empty()                   {return length == 0; }
int is_full()                    {return length == MAX_LIST_SIZE; }
int get_entry(int num)           {return data[num]; }
void replace(int num, Element e) {data[num] = e; }
int size() {return length; }

void insert(int pos, int e ){
    if(is_full==0 && pos >= 0 && pos<=length){
        for(int i = length ; i>pos ; i--){
            data[i] = data[i-1];
        }
        data[pos] = e;
        length++;
    }
    else error ("Saturation & Error || Insertion Position Error".");
}

void delete(int pos)
{
    if(is_empty()==0 && 0 <= pos && pos < length){
        for(int i=pos+1 ; i < length ; i++ ){
            data[i-1] = data[i];
            length--;
        }
    }
    else error ("Blank Status Error || Delete Location Error");
}

int find (Element e)
{
    for(int i = 0 ; i < length ; i++){
        if(data[i] == e ){
            return i;
        }
    }
    return -1;
}

void print_list(){
    for(int i = 0 ; i < length ; i++){
        printf("%2d", data[i]);
    }
    printf("\n");
}


void main()
{
    init_list();
    insert(0, 10);
    print_list();
}