C language implements sequence table - data structure

#include <stdio.h>
#include <stdlib.h>
//Requirement, write a sequential linear table and store an address position
#define LIST_INIT_SIZE 100 //The initial allocation of linear table storage space
#define LISTINCREMENT 10 //Linear table Allocation increment of storage space
#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define INFEASIBLE -1
#define OVERFLOW -2
typedef int Status; //function result status code

typedef struct{
    int x;
    int y ;
}Point2D;

typedef struct{
    Point2D * element; //Base address of storage space
    int length; //Current length
    int listsize; //Currently allocated storage capacity (in sizeof(elementType))
}SqList;

//Initialization sequence table
Status InitList(SqList * L){
     //Allocate a listsize space (now element is an array)
    L->element=(Point2D*)malloc(LIST_INIT_SIZE*sizeof(Point2D));
    if(!L ->element){
        //No space is applied for
        exit(OVERFLOW);
    }
    //After the application is successful, the length is set to 0
    L->length=0;
    L->listsize=LIST_INIT_SIZE;
    return OK;
}

//Insert elements ( Insert data p before the i-th position inserted in the sequence table)
Status ListInsert(SqList * L,int i,Point2D p){
    int j;
    //Determine whether the inserted position is legal
    //The legal position of i is 1 ListLength( L)+1
    if(i<1||i>L->length+1){
        //The range of i is illegal
        return ERROR;
    }
    if(L->length>=L->listsize){
        //If it is greater than or equal to the maximum allocation length, it means that memory needs to be re-allocated
        Point2D * p=(Point2D*)realloc(L->element,(L-> listsize+LISTINCREMENT)*sizeof(Point2D));
        if(!p){
            //If it is empty, it means the allocation failed
            return ERROR;
        }
        //The allocation is successful
        L->element=p; //The new base address
        L->listsize+ =LISTINCREMENT;    
    }
    //If all are valid, insert the data, move the i-th position and the elements after it by one position
    
    for(j=L->length-1;j>=i-1; j--){
        L->element[j+1]=L->element[j];
    }
    //Write the data in the i-1 space
    L->element[i-1]=p;
    //The length add 1
    L->length++;
    return OK;
}

//合并顺序列表(将l1和l2中的元素给合并到l3中) l3必须在外面就进行分配内存空间
void MergeList(SqList l1,SqList l2,SqList *l3){
    Point2D *l1_last,*l2_last;
    Point2D *l1_start,*l2_start,*l3_start;
    int i=l1.length+l2.length;
    l3->length=l3->listsize=i;
    l3_start=l3->element=(Point2D*)malloc(sizeof(Point2D));
    if(!l3){
        exit(OVERFLOW);
    }
    l1_start=l1.element;
    l2_start=l2.element;
    l1_last=l1.element+l1.length-1;
    l2_last=l2.element+l2.length-1;

    while(l1_start<=l1_last&&l2_start<=l2_last){
        if(l1_start->x>l2_start->x){
            *l3_start=*l1_start;
            l3_start++;
            l1_start++;
        }else if(l1_start->x<l2_start->x){
            *l3_start=*l2_start;
            l3_start++;
            l2_start++;
        }else{
            //相等
            *l3_start=*l2_start;
            l3_start++;
            l2_start++;
            l1_start++;
        }
    }
    while(l1_start<=l1_last){
        *l3_start=*l1_start;
        l3_start++;
        l1_start++;
    }

    while(l2_start<=l2_last){
        *l3_start=*l2_start;
        l3_start++;
        l2_start;
    }
}


//Test
int main(){
    int i;
    SqList * L1=(SqList *)malloc(sizeof(SqList));
    Point2D p={1,2};
    //Initialize a pointer to a structure
    / /The structure allocates a space to store the first address of the array, the length of the array, and the maximum capacity of the array
    SqList * L=(SqList*)malloc(sizeof(SqList));        
    i=InitList(L);
    if(i= =OK){
        printf("Created successfully");
    }
    i=ListInsert(L,1,p);
    if(i==OK){
        printf("Insert successfully");
    }
    i=ListInsert(L,2,p );
    //Print the inserted data element
    printf("Data x is %d, data y is: %d, the length of the sequence table is %d", L->element[0].x, L->element[0 ].y,L->length);
    
    printf("hello world");
    printf("Create a new set of sequence lists");
    
    MergeList(*L,*L,L1);
    printf("The length of the merged sequence list is %d, and the total capacity is % d\n",L1->length,L1->listsize);
    while(L1->element->x){
        printf("The x value of the data:%d\n",L1->element->x) ;
        L1->element++;
    }
    scanf("%d",&i);
}