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(8, '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(0, 3, 'A');
cout << s <<endl;

s.insert(5, s2);    //位置从0开始，第6个元素之前
cout << s <<endl;

s2 = "12345";
s.insert(0, s2, 2, 3);
cout << s <<endl;

char *cp = "Stately plump Buck";
s.assign(cp, 7);
cout << s <<endl;
s.assign(cp);
cout << s <<endl;

s = "hello";
s.insert(0, cp, 7);
cout << s <<endl;
s = "hello";
s.insert(0, cp);
cout << s <<endl;

s = "hello";
s2 = "abcdef";
s.assign(s2, 2, 3);
cout << s << endl;

s.erase(2, 3);
cout << s <<endl;

s = "123456789";
s.erase(s.size()-5, 1); //删除字符串的倒数第5个；
cout << s <<endl;

s.insert(s.size(), 5, '!'); //size()最后一个的后一个，insert在size（）之前插入；
cout << s <<endl;

s = "abc";
s.erase(0, 1).insert(0, "A");
cout << s <<endl;

s = "abc";
s[0] = 'A';
cout << s <<endl;
return 0;
}

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(6, 5); //从第7个位置开始的5个字符；
string s3 = s.substr(6, 50);    //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(6);
cout << s2 << endl;

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

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

s.replace(11, 3, "4th");    //字符串替换
cout << s << endl;

s.replace(11, 3, "AAAAAA");
cout << s << endl;

return 0;
}

#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("0123456789");
string::size_type pos = 0;
//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 = 0;
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 0;
}