cin.get();
}
14)
//clear() 删除全部字符
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s = "abcdefg";
cout<<s.length()<<endl;
s.clear();
cout<<s.length()<<endl;
//使用earse方法变相全删除
s = "dkjfd";
cout<<s.length()<<endl;
s.erase(0,s.length());
cout<<s.length()<<endl;
cin.get();
}
15)
//replace() 替换字符
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s = "abcdefg";
s.replace(2,3,"!!!!!");//从索引2开始3个字节的字符全替换成"!!!!!"
cout<<s<<endl;
cin.get();
}
16)
//==,!=,<,<=,>,>=,compare() 比较字符串
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s1 = "abcdefg";
string s2 = "abcdefg";
if (s1==s2)cout<<"s1 == s2"<<endl;
else cout<<"s1 != s2"<<endl;
if (s1!=s2)cout<<"s1 != s2"<<endl;
else cout<<"s1 == s2"<<endl;
if (s1>s2)cout<<"s1 > s2"<<endl;
else cout<<"s1 <= s2"<<endl;
if (s1<=s2)cout<<"s1 <= s2"<<endl;
else cout<<"s1 > s2"<<endl;
cin.get();
}
17)
//size(),length() 返回字符数量
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s = "abcdefg";
cout<<s.size()<<endl;
cout<<s.length()<<endl;
cin.get();
}
18)
//max_size() 返回字符的可能最大个数
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s = "abcdefg";
cout<<s.max_size()<<endl;
cin.get();
}
19)
//empty() 判断字符串是否为空
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s ;
if (s.empty())
cout<<"s 为空."<<endl;
else
cout<<"s 不为空."<<endl;
s = s + "abcdefg";
if (s.empty())
cout<<"s 为空."<<endl;
else
cout<<"s 不为空."<<endl;
cin.get();
}
20)
// [ ], at() 存取单一字符
#include <string>
#include <iostream>
using namespace std;
void main()
{
string s = "abcdefg1111";
cout<<"use []:"<<endl;
for(int i=0; i<s.length(); i++)
{
cout<<s[i]<<endl;
}
cout&l