1
2
3
vector<double> arr(n); //创建元素个数为n的数组对象
vector<int> v = {1, 2, 3};  //创建

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
#include <iostream>
#include <vector>  //注意//
using namespace std;

//计算数组arr中元素的平均值
double average(const vector<double>& aaa) //vector<double>类型的数据，类似const int& a普通变量的传递
{  //有size()函数，无需传数组个数过来
	double sum = 0;
	for (unsigned i = 0; i < aaa.size(); i++)
		sum += aaa[i];
	return sum / aaa.size();
}

int main() {
	unsigned n;
	cout << "n = ";
	cin >> n;
	vector<double> arr(n); //创建数组对象
	cout << "Please input " << n << " real numbers:" << endl;
	for (unsigned i = 0; i < n; i++)
		cin >> arr[i]; //可以用数组名下标的方式来访问每一个元素。
	cout << "Average = " << average(arr) << endl;
	return 0;
}

1
2
3
4
5
6
7
8
9
10
11
12
#include <vector>
#include <iostream>
int main()
{
	std::vector<int> v = { 1,2,3 };
	for (auto i = v.begin(); i != v.end(); ++i)
		std::cout << *i << std::endl;
	for (auto e : v)
		std::cout << e<< std::endl;
	return 0;
}

1
2
3
4
5
6
7
void fun1(const int& a){
	a += 4;  //error，a不可修改
}
int main(){
	int b = 5;
	fun1(b);}

1
2
3
4
5
6
7
8
void fun2(const int* a){
	cout << *(a+1) + 3 <<endl;  //输出5
}
int main(){
	int array[2] = {1, 2};
	fun2(array);
	}