C++ 提高教程 STL vector容量-vector容量和大小

Posted 2021-10-31 行码阁119

# include<iostream>
#include<vector>
# include<algorithm>
# include<string>
using namespace std;

void printVector(vector<int>& v)
{
	for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
	{
		cout << *it << " ";
	}
	cout << endl;
}
void test01()
{
	vector<int>v1;
	for(int i =0;i<10;i++)
	{
		v1.push_back(i);
	}
	printVector(v1);

	if (v1.empty()) //为真，代表容器为空
	{
		cout << "v1为空" << endl;
	
	}
	else
	{
		cout << "v1不为空" << endl;
		cout << "v1容量为："<<v1.capacity() << endl;
		cout << "v1的大小为：" << v1.size() << endl;
	}

	//重新指定大小
	v1.resize(15,100);
	printVector(v1);  //如果指定的比原来长了。只有通过填充实现

	v1.resize(5);
	printVector(v1);  //如果重新指定的比原来短了，超出的部分删除
}
int main()
{
	test01();
	system("pause");
	return 0;
}