What is wrong in below code? this code resulted in illegal memory access and the program is terminated by os.

Question

tuple <string,string,string> t1;
t1=make_tuple("a1","b1","c1");
string tag="a1",a,b,c;
tie(a,b,c)=t1;
if(a==tag){
return a;
}
//Above code is a member function
//"tag" is the member variable of object

Answer 1

got it,
access the member variable "tag" with "this->tag";
if(a==this->tag){
return a;
}