STL之string插入

 #include <iostream>
 #include <string>

 using namespace std;
 int main()
 {
     string s("hello");
     string s2("abcdef");

     string::iterator p = s.begin();
     cout << *p << endl;
     s.insert(p, 'A');   //插入之后，p指向新插入的数据
     cout << *p << endl;
     cout << s << endl;

     //每执行插入操作一次，gcc下必须重新给迭代器赋值
     //否则内存泄漏
     // 为什么呢？不明白
     p = s.begin();
     s.insert(p,'B');
     cout << *p << endl;
     cout << s << endl;

     string::iterator b = s2.begin();
     string::iterator e = s2.end();

     p = s.begin();
     s.insert(p, b, e);
     cout << s << endl;

     s = "hello";
     cout << s <<endl;
     s.assign(b, e);
     cout << s <<endl;

     s.assign(, 'k');
     cout << s <<endl;

     s = "abcdef";
     p = s.begin();
     s.erase(p);     //删除
     cout << s <<endl;

     p = s.begin();
     p++;
     p++;
     string::iterator p2 = s.end();
     p2--;
     s.erase(p, p2);
     cout << s <<endl;

     s = "hello";
     s2 = "abc";
     s.insert(, , 'A');
     cout << s <<endl;

     s.insert(, s2);    //位置从0开始，第6个元素之前
     cout << s <<endl;

     s2 = "";
     s.insert(, s2, , );
     cout << s <<endl;

     char *cp = "Stately plump Buck";
     s.assign(cp, );
     cout << s <<endl;
     s.assign(cp);
     cout << s <<endl;

     s = "hello";
     s.insert(, cp, );
     cout << s <<endl;
     s = "hello";
     s.insert(, cp);
     cout << s <<endl;

     s = "hello";
     s2 = "abcdef";
     s.assign(s2, , );
     cout << s << endl;

     s.erase(, );
     cout << s <<endl;

     s = "";
     s.erase(s.size()-, ); //删除字符串的倒数第5个；
     cout << s <<endl;

     s.insert(s.size(), , '!'); //size()最后一个的后一个，insert在size（）之前插入；
     cout << s <<endl;

     s = "abc";
     s.erase(, ).insert(, "A");
     cout << s <<endl;

     s = "abc";
     s[] = 'A';
     cout << s <<endl;
     return ;
 }
        

只适合string的操作：

　　获取子串：substr（）函数；--------3个重载函数

　　替换函数：replace（）函数；-------6个重载函数

　　尾加函数：append（）函数;--------10个重载函数；

 #include <iostream>
 #include <string>

 using namespace std;

 int main()
 {
     string s("hello world");
     string s2 = s.substr(, ); //从第7个位置开始的5个字符；
     string s3 = s.substr(, );    //从第7个位置开始的50个字符,实际上达不到50个；
     cout << s3 << endl;

     s2 = s.substr();
     cout << s2 << endl;

     s = "C++ Primer";
     s.append(" 3rd Ed. ");
     cout << s << endl;

     s.insert(s.size(), " 3rd Ed. ");
     cout << s << endl;

     s.replace(, , "4th");    //字符串替换
     cout << s << endl;

     s.replace(, , "AAAAAA");
     cout << s << endl;

     return ;
 }

 #include <iostream>
 #include <string>

 using namespace std;

 int main()
 {
     string name("AnnmaBelle");
     string::size_type pos1= name.find("Bell");
     if(pos1 == string::npos){
         cout << "not find" << endl;
     }else{
         cout << "find it, pos: " << pos1 << endl;   //pos1 = 4;
     }   

     name = "r2d3";
     string num("");
     string::size_type pos = ;
     //find_first_of(), 查找name中的任意一个字符即返回；
     //查找name中数字,反之可以找字母
     //与之对应的是：find_last_of
     while((pos = name.find_first_of(num, pos))!=string::npos){
         cout << name[pos] << endl;
         pos++;
     }   

     //find_first_not_of(),从num中查找name中字符，没有找到即返回string::npos
     //与之对应的是：find_last_not_of
     pos = ;
     while((pos=name.find_first_not_of(num, pos))!=string::npos){
         cout << name[pos] << endl;
         ++pos;
     }

     string river("Mississippi");
     string::size_type first_pos = river.find("is"); //从前向后操作，找到第一个即返回,返回值是下标
     if(first_pos != string::npos)
         cout <<"first_pos: "<< first_pos << endl;
     first_pos = river.rfind("is");  //从后向前操作，找到第一个即返回,返回值是下标
     if(first_pos != string::npos)
         cout <<"last_pos: "<< first_pos << endl;

     return ;
 }