Using find in map with user defined class as key - c++

Question

I have define a class Entry with 2 integer values a and b, and a vector of Entry 'e'. Now, I am going to define a map' m' of Entry and int where int is number of time that entry appear in vector. The thing is find function is considering Entry(1,2),Entry(1,12) and Entry(1,13) as one. Two entries should be same when both a and b are equal. But here if only a is equal its considering the two entries as same.
#include<iostream>
#include<map>
#include<vector>
using namespace std;
class Entry{
public:
int a;
int b;
Entry(int,int);
bool operator <(Entry);
bool operator >(Entry);
bool operator ==(Entry);
};
Entry::Entry(int x,int y):a(x),b(y){
}
bool Entry::operator ==(Entry e){
if(a==e.a && b==e.b)
return true;
else
return false;
}
bool Entry:: operator <(Entry e){
if(a<e.a)
return 1;
else
return 0;
}
bool Entry:: operator >(Entry e){
if(a>e.a)
return 1;
else
return 0;
}
int main(){
map<Entry,int> m;
vector<Entry> e;
e.push_back(Entry(1,2));
e.push_back(Entry(10,21));
e.push_back(Entry(1,13));
e.push_back(Entry(1,2));
e.push_back(Entry(1,12));
for(int i=0;i<e.size();i++){
if(m.find(e[i])==m.end())
m[e[i]]=1;
else{
m[e[i]]=m[e[i]]+1;cout<<e[i].a<<" "<<e[i].b<<" "<<m[e[i]]<<endl;
}
}
}

Answer 1

std::map is using the relational operator < for ordering and checking key uniqueness. Since your implementations of operator< use the a member only for comparing it will ignore b when evaluating key equality. operator== is not used from the map interface - it is replaced by !(a < b || b < a). You need something like
bool Entry::operator<(const Entry& e){
return a < e.a || a == e.a && b < e.b;
}
You could remove operator> and operator== or keep them if you need them for other purposes.