string类的八个构造函数用法

//str1.cpp -- introducing the string class
#include <iostream>
#include <string>
//using string constructors

int main()
{
	using namespace std;
	string one("Lottery Winner");  //第一种构造函数
	cout << one << endl;           //"<<"运算符的重载用法
	string two (20, '$');          //创建一个包含n个元素的对象，其中每个元素都被初始化为‘$’字符
	cout << two <<endl;
	string three(one);             //将three对象初始化为one对象（使用复制构造函数）
	cout << three << endl;
	one += "Oops";                 //"+="运算符的重载用法
	cout << one << endl;
	two = "Sorry! That was ";
	three[0] = 'p';                //'[]'运算符的重载用法
	string four;                   //默认构造函数
	four = two + three;
	cout << four << endl;
	char alls[] = "All's well that ends well ";
	string five(alls, 20);         //将five对象初始化为alls所指向的字符串的前20个字符
	cout << five << endl;
	string six( alls + 6, alls + 10); //将six对象初始化为alls+6和alls+10之间的字符，包括alls+6但不包括alls+10
	cout << six << ",";
	string seven ( &five[6], &five[10]);  //构造函数同上，不同的是参数形式有所变化
	cout << seven << "...\n";
	string eight(four, 7, 16);
	cout << eight << " in motion " << endl;
	cin.get();
	return 0;
}

测试效果如图：