string length()

#include <set>
std::set<std::string> setName;
int main()
{
    std::string strName = "世界英雄aa";//中文占两个字节，英文占一个字节
    const char* name = strName.c_str();
    int length = strName.length();//10
    length = strlen(name);//10
    return 0;
}