string::find_last_of

string (1)	size_t find_last_of (const string& str, size_t pos = npos) const noexcept;
c-string (2)	size_t find_last_of (const char* s, size_t pos = npos) const;
buffer (3)	size_t find_last_of (const char* s, size_t pos, size_t n) const;
character (4)	size_t find_last_of (char c, size_t pos = npos) const noexcept;

#include <iostream>
#include <string>

using namespace std;

int main()
{
string s1("abcdef");
string s2("ghif");
cout << s1.find_last_of(s2) << endl;
cout << s1.find_last_of(s2, 4) << endl;s2中查找s1位置<=4的字符
const char *s3 = "abcdeghi";
cout << s1.find_last_of(s3) << endl;
cout << s1.find_last_of(s3,3) << endl;//s3中查找s1的位置3之前包括位置3
cout << s1.find_last_of(s3,3,3) << endl;//s3的前3个中查找s1的位置<=3的字符
cout << s1.find_last_of('e', 3) << endl;
if(s1.find_last_of('e', 3) == string::npos)
cout << "string::npos\n";
return 0;
}