C++ Primer笔记（一）：字符串、向量和数组

3.1 命名空间

• using namespace::name;
• using namespace::std
• using std::cin
  
  ……
  
  头文件不应该包含using

---

3.2 类型string

getline(cin, str);
str.empty();
str.size();

size()返回类型为UINT，不能与int比较，当int为负时出错

string对象只能和string对象或字面值相加

循环处理

for(auto c : str)
{}

for(auto &c : str)
{}

习题3.2.3

#include "stdafx.h"
#include <iostream>
#include <string>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	string str;

	cout << "3.6" << endl;
	str = "aruew32413aefjewoiroqw1231./awrfwer";
	cout << str << endl;
	for (auto &i : str)
	{
		i = 'X';
	}
	cout << str << endl;

	cout << "3.7" << endl;
	str = "aruew32413aefjewoiroqw1231./awrfwer";
	cout << str << endl;
	for (auto i : str)
	{
		i = 'X';
	}
	cout << str << endl;

	cout << "3.10:Enter a string including punctuation." << endl;
	getline(cin, str);
	for (auto i : str)
		if (!ispunct(i)) cout << i;
	cout << endl;

	cout << "3.11" << endl;
	const string s = "hello";
	for (auto &i : s)
	{
		cout << typeid(i).name() << endl;
		break;
	}

	return 0;
}

待续……