C language arrangement question

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

typedef int Element;
Element data[MAX_LIST_SIZE];
int length = 0;
    int pic = 0;
    int pic2 = 0;
    int add_num = 0;
    int place = 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 ){
            printf("%d",data[i]);
        }
        else error ("input error");
    }
}

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

void prompt_2(){
    printf("Select where to add or delete nodes"\n");
    printf("1. Front 2. Back 3. Select Location\n");
    printf ("Select menu: ");
    printf("\n");
}


void main(){   
    /*
    do{
        prompt_1();
        scanf("%d",&pic);
        if(pic == 1){
           for 
        }
        /*if(pic == 2){
            prompt_2();
            delete();
        }
        if(pic == 3){
            find();
        }
        if(pic == 4){
            printf("Current Array Status: ");
            print_list();
        }
    }while(pic != 5);
    */
    while (1) {
        printf ("Select the action to execute\n");
        printf("1. Add nodes 2. Delete nodes 3. Search nodes 4. Output nodes 5. Select the End \n menu: ");
        scanf("%d", &pic);

        if (pic >= 1 && pic != 5) {
            switch (pic) {
                case 1 :

                    printf("Set insertable :");
                    scanf("%d", &add_num);
                    printf ("Select a location to insert\n");
                    printf("1. Front, 2. Back, 3. User location setting : ");"
                    scanf("%d", &pic2);
                    if(pic2 == 1){
                        insert(0,add_num);
                    }
                    else if(pic2 == 2){
                        insert(length,add_num);
                    }
                    else if(pic2 == 3){
                        printf("Set the location to insert (0~):");
                        scanf("%d", &place);
                        insert(place,add_num);
                    }

                    printf ("Inserted".\n\n");

                    break;
                case 2 :
                    printf("Set the location to be removed (0~): ");"
                    scanf("%d", &place);
                    delete(place);

                    printf ("Removed".\n\n");
                    break;
                case 3 :
                    printf("Set search location:");"
                    scanf("%d",&place);
                    find(place);
                    break;
                 case 4 :
                    printf("\n");
                    print_list();
                    break;
                default :
                    printf("Invalid value". Please re-enter.\n\n");
                    break;
            }
        }
        else if(pic == 5)
        break;
    }


}