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  1. #include<iostream>
  2. #include<string>
  3. #include<unordered_map>
  4. using namespace std;
  5. class student{
  6. public:
  7.     string firstname;
  8.     string lastname;
  9.     string rollno;
  10.  
  11.     student(string f,string l, string n){
  12.         firstname = f;
  13.         lastname = l;
  14.         rollno = n;
  15.     }
  16.     bool operator == (const student &s)const{
  17.         return rollno == s.rollno;
  18.     }
  19. };
  20.  
  21. class Hashfn{
  22. public:
  23.     size_t operator()(const student &s)const{
  24.         return s.firstname.length() + s.lastname.length();
  25.     }
  26. };
  27. int main(){
  28.  
  29.     unordered_map<student,int,Hashfn> student_map;
  30.     student s1("pratek", "narang", "010");
  31.     student s2("rahul", "kumar", "023");
  32.     student s3("pratek", "gupta", "030");
  33.     student s4("rahul", "kumar", "120");
  34.  
  35.     //add student marks to hashmap
  36.     student_map[s1] = 100;
  37.     student_map[s2] = 80;
  38.     student_map[s3] = 90;
  39.     student_map[s3] = 70;
  40.  
  41.     for(auto s:student_map){
  42.         cout<<s.first.firstname<<" "<<s.first.rollno<<"marks"<<s.second<<endl;
  43.     }
  44.  
  45. return 0;}
  46.  
Success #stdin #stdout 0s 4336KB
comments (?)
stdin 
Standard input is empty
stdout 
pratek 030marks70
pratek 010marks100
rahul 023marks80
https://ideone.com/CSvnPb
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
secret

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