Description This function returns a reverse iterator pointing ot the element right before the first key value pair in the map
Example :
#include <iostream>
#include<map>
using namespace std;
int main(){
map<char,int> mymap;
mymap.insert(make_pair('a',1));
mymap.insert(make_pair('b',3));
mymap.insert(make_pair('c',5));
for(auto i = mymap.rbegin(); i != mymap.rend();i++){
cout<< i -> first << " = " << i -> second << endl;
}
return 0;
}