# Struct --- 當需要處存的資料有非常多的細項且會重複 ex. 遊戲角色 - 需要處存HP、攻擊力、防禦力等 --- 宣告 ```cpp struct Player{ string name; int HP,attack,defense; }; Player Data; Data.HP = 100; ``` ---- 可是這樣只能儲存一位角色 -->用陣列解決！ `Player Data[100]` ```cpp Data[0].HP = 100;//第0位玩家的HP設為100 ``` ---- 怎麼初始化? ```cpp struct Player{ string name = ""; int HP = 100,attack = 10,defense = 10; }; ``` --- 進階用法 ---- ```cpp using namespace std; #define int long long struct vec{//向量 int x,y,r; vec(int _x = 0,int _y = 0) : x(_x),y(_y){ r = sqrt(x*x+y*y); }//建構函數(建構子) void PrintVec(){ cout<<x<<" "<<y<<" "<<r<<"\n"; }//void函數 int ReturnVec(){ return r; }//int函數 int ChangeVec(int _x,int _y){ x = _x;y = _y; r = sqrt(x*x+y*y); }//void函數 }; signed main(){ vec p1(3,4); p1.PrintVec(); p1.ChangeVec(5,12); p1.PrintVec(); int _r = p1.ReturnVec(); cout<<_r; return 0; } ```