#include <stdio.h>
#define MaxLength 20
typedef int ElementType;
typedef int Position;

typedef struct {
	ElementType Elements[MaxLength];
	Position Last;
} List;

void MakeNullList(List *L) {
	L->Last = 0;
};
int EmptyList(List L) {
	return L.Last == 0;	
};
Position EndList(List L) {
	return L.Last + 1;
}
Position First(List L) {
	return 1;
}
Position Next(Position P, List L) {
	return P + 1;
}
ElementType Retrieve(Position P, List L) {
	return L.Elements[P-1];
}
void InsertList(ElementType X, Position P, List *L) {
	if(L->Last == MaxLength) printf("Mang day");
	else if((P<1) || (P>L->Last+1)) printf("Vi tri khong hop le");	
	else {
		Position Q;
		for(Q = (L->Last - 1)+1; Q > P-1; Q--) {
			L->Elements[Q] = L->Elements[Q-1];
		};
		L->Elements[P-1] = X;
		L->Last++;
	}
};
void DeleteList(Position P, List *L) {
	if((P<1) || (P>L->Last)) printf("Vi tri khong hop le");
	else if(EmptyList(*L)) printf("ds rong");
	else {
		Position Q;
		for(Q = P-1; Q<L->Last-1; Q++) {
			L->Elements[Q] = L->Elements[Q+1];
		};
		L->Last--;
	}
};
Position Locate(ElementType X, List L) {
	Position P;
	int Found = 0;
	P = First(L);
	while(P != EndList(L) && Found == 0) {
		if(X == Retrieve(P, L)) Found = 1;
		else P = Next(P, L);
	};
	return P;
}
void ReadList(List *L) {
	int i,n;
	ElementType X;
	MakeNullList(&(*L));
	printf("Nhap vao so phan tu: "); scanf("%d", &n);
	for(i = 1; i<=n; i++) {
		printf("Nhap vao phan tu thu %d: ", i); scanf("%d", &X);
		InsertList(X, i, &(*L));
	};
}
void PrintList(List L) {
	for(int i = 1; i<=L.Last; i++) {
		printf("%d", Retrieve(i, L));
	};
	printf("\n");
}

int main() {
	List L;
	ElementType X;
	Position P;
	ReadList(&L);
	printf("Ds da nhap la: ");
	PrintList(L);
	printf("Nhap vao phan tu muon xen: "); scanf("%d", &X);
	printf("Nhap vao vi tri muon xen: "); scanf("%d", &P);
	InsertList(X, P, &L);
	printf("Ds da nhap la: "); 
	PrintList(L);
	printf("Nhap vao phan tu muon xoa: "); scanf("%d", &X);
	P = Locate(X, L);
	DeleteList(P, &L);
	printf("Ds da nhap la: "); 
	PrintList(L);
}