c/c++ 標準庫 vector 標準庫 vector的小例子 test1~test7 c++ include include using namespace std; class A{ public: A(){cout v1; vector v2; / //test2 / vector v3(2) ...
c/c++ 標準庫 vector
標準庫 vector的小例子
test1~test7
#include <iostream>
#include <vector>
using namespace std;
class A{
public:
A(){cout << "AA" << endl;}
};
int main(){
//test1
/*
vector<int> v1;
vector<vector<string>> v2;
*/
//test2
/*
vector<A> v3(2);//創建2個元素的vector
//因為v4所提供的值不能作為元素的初始值，
//所以編譯器嘗試用預設值初始化vector，所以{4}的含義就變成了(4),
//也就是創建了4個元素的vector
vector<A> v4{4};//創建4個元素的vector
vector<int> v5{15};//創建1個元素的vector
for(auto a : v5){
cout << a << endl;
}
*/
//test3
/*
vector<int> v1;//size:0
cout << v1.size() << endl;
vector<int> v2(10);//size:10
cout << v2.size() << endl;
vector<int> v3(10, 12);//size:10
cout << v3.size() << endl;
vector<int> v4{11};//size:1
cout << v4.size() << endl;
vector<int> v5{10, 12};//size:2
cout << v5.size() << endl;
vector<string> v6{10};//size:10
cout << v6.size() << endl;
vector<string> v7{10, "ab"};//size:10
cout << v7.size() << endl;
*/
//test4
/*
vector<int> v;
int s;
while(cin >> s){
v.push_back(s);
}
cout << v.size() << endl;
*/
//test5
/*
vector<string> v;
string s;
while(cin >> s){
v.push_back(s);
}
cout << v.size() << endl;
*/
//test6
/*
//vector::size_type t;編譯不過，必須帶<int>
vector<int>::size_type t;
*/
//test7
/*
vector<int> v(11, 0);
int grade;
while(cin >> grade){
if(grade <= 100)
++v[grade / 10];
}
for(auto a : v){
cout << a << " ";
}
cout << endl;
*/
}
