20170728_vector实现二维数组

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最新推荐文章于 2024-10-05 10:29:41 发布

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分类专栏： C++STL源码剖析文章标签： vector实现二维数组

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20170728_vector实现二维数组

/*
vector 实现二维数组
*/
#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;

int main(void)
{
	vector<vector<int>> martix(10);	//小括号不能省，代表的是行数！
	for(int i=0; i<10; ++i)
	{
		for(int j=0; j<6; ++j)
		{
			martix[i].push_back(10*j+i);
		}
	}
	cout<<martix.size()<<endl;		//输出行数  10
	cout<<martix[0].size()<<endl;	//输出列数  6

	for(auto col:martix)
	{
		for(auto mem:col)
		{
			cout<<mem<<",";
		}
		cout<<endl;
	}
	cout<<endl;

	system("pause");
	return 0;
}

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

int main(void)
{
	int n[]={1,2,3,4,5,6,7,8,9,10};
	vector<int> ivec(begin(n),end(n));
	//vector<int> ivec(1024);
	int num1=ivec.size();		//num1=10
	int num2=ivec.capacity();	//num2=10
	cout<<num1<<","<<num2<<endl;

	for(int i=50; i<100; ++i)
		ivec.push_back(i);
	int num3=ivec.size();		//num3=60=50+10
	int num4=ivec.capacity();	//num4=73
	cout<<num3<<","<<num4<<endl;

	ivec.shrink_to_fit();
	cout<<ivec.size()<<","<<ivec.capacity()<<endl;	//60,60

	ivec.resize(100);
	cout<<ivec.size()<<","<<ivec.capacity()<<endl;	//100,100

	system("pause");
	return 0;
}