string::find_first_not_of

string (1)	size_t find_first_not_of (const string& str, size_t pos = 0) const noexcept;
c-string (2)	size_t find_first_not_of (const char* s, size_t pos = 0) const;
buffer (3)	size_t find_first_not_of (const char* s, size_t pos, size_t n) const;
character (4)	size_t find_first_not_of (char c, size_t pos = 0) const noexcept;

功能：查找在前面出现后面没有的位置

返回值：成功返回找到的位置，没找到返回string::npos

#include <iostream>
#include <string>

using namespace std;

int main()
{
string s1("abcde");
string s2("aaccbbddeeff");
size_t n = s2.find_first_not_of(s1);
cout << n << endl;
const char *s3 = "abcdefghij";
string s4("mabcdefghijk");
cout << s4.find_first_not_of(s3) << endl;
cout << s4.find_first_not_of(s3, 1) << endl;
cout << s4.find_first_not_of(s3, 1, 5) << endl;
string s5("mabcdefghij");
cout << (n = s5.find_first_not_of(s3, 1)) << endl;
if(n == string::npos)
cout << "not found diffence string::npos" << endl;
return 0;
}