学步园

#include <iostream>

int main() 
{
	std::cout << " liaojianguo "
                  << " is 笨蛋 "
                  << std::endl;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ -o main main.cc
pateo@pateo-B86N53X:~/work/study$ ./main
 liaojianguo  is 笨蛋 

string有很多很多函数方法，在这不一一列举

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	int n;
	string s1;
	string s3("大笨蛋");
        cin >> s1 ;
	string s2(s1);
        cout << "s1=" << s1 << " s2=" << s2 << " s3=" << s3 << endl;

        return 0;
}

输出：

pateo@pateo-B86N53X:~/work/study$ ./main
liaojianguo
s1=liaojianguo s2=liaojianguo s3=value

getline

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	string line;
        while(getline(cin,line))
  		cout << line << endl;
        return 0;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ -o main main.cc
pateo@pateo-B86N53X:~/work/study$ ./main
liaojianguo 
liaojianguo 
wo shi hao haizi
wo shi hao haizi

empyt

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	string st ;
        if(st.empty())
	{
	   cout <<  "st is empty" << endl;
	}
        return 0;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ -o main main.cc
pateo@pateo-B86N53X:~/work/study$ ./main
st is empty

size

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	string st("liaojianguo") ;

	cout <<  "st size is " << st.size() << endl;

        return 0;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ -o main main.cc
pateo@pateo-B86N53X:~/work/study$ ./main
st size is 11

关系操作符

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	string big = "big";
        string small = "small";
        if(big == small)
	{
		cout << "big == small" <<endl;
	}else if(big < small)
	{
		cout << "big < small" <<endl;
	}else if(big > small)
	{
		cout << "big > small" <<endl;
	}
        return 0;
}

pateo@pateo-B86N53X:~/work/study$ ./main
big < small

说明：比较规则

1、如果两个string对象长度不同，且短的string对象与长的string对象的前面部分相匹配，则短的string对象小于长的string对象

2、== 标识相等，！=标识不相等

3、如果两个string对象的字符不同，则比较第一个不匹配的字符,大小写敏感，采用了和字典排序相同的策略

字符连接与下标操作

#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::string;
int main()
{
	string big = "big";
        string small = "small";
        string big_small = big + small;
        big_small += big;
        cout << big_small << endl;
        
        for(string::size_type ix = 0; ix != big_small.size(); ++ix)
	{
		cout << big_small[ix] << endl;
	}
        return 0;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ -o main main.cc
pateo@pateo-B86N53X:~/work/study$ ./main
bigsmallbig
b
i
g
s
m
a
l
l
b
i
g
pateo@pateo-B86N53X:~/work/study$ 

#include <iostream>
#include <string>
using std::string;
using std::cout;
using std::endl;
void revoke(const string &);
int main(int argc, char *argv[])
{
 string a("hello\n");
 revoke(a);
 cout<<"a value is= "<<a;
 return 0;
}
void revoke(const string &abc)
{
 string cc(abc);
 cout<<cc;
}

输出：

pateo@pateo-B86N53X:~/work/study$ g++ main.cc -o main
pateo@pateo-B86N53X:~/work/study$ ./main
hello
a value is= hello
pateo@pateo-B86N53X:~/work/study$