原型为：unsigned int find(const basic_string &str) const;
作用：查找并返回str在本串中第一次出现的位置，位置从0开始
例子如下：
#include <iostream>
using namespace std;
int main() {
string str = "i love china. china love me";
string find_str = "love";
cout << str.find(find_str); // 2
return 0;
}
string append(const char* s) ;
#include <iostream>
using namespace std;
int main() {
string str = "i love china. ";
char append_str[] = "china love me";
cout << str.append(append_str) << endl; // i love china. china love me
cout << str << endl; // i love china. china love me
return 0;
}
string & insert(unsigned int p0, const char * s);
#include <iostream>
using namespace std;
int main() {
string str = "i love . china love me";
char insert_str[] = "china";
cout << str.insert(7, insert_str) << endl; // i love china. china love me
cout << str << endl; // i love china. china love me
return 0;
}
string substr(unsigned int pos, unsigned int n) const;
#include <iostream>
using namespace std;
int main() {
string str = "i love china. china love me";
cout << str.substr(2, 22) << endl; // love china. china love
return 0;
}
string & erase(unsigned int pos);string & erase(unsigned int pos， unsigned int n);
#include <iostream>
using namespace std;
int main() {
string str1 = "i love china. china love me";
cout << str1.erase(12) << endl; // i love china
cout << str1 << endl; // i love china
string str2 = "i love china. china love me";
cout << str2.erase(7, 18) << endl; // i love me
cout << str2 << endl; // i love me
return 0;
}
