Hash Table

//using stringstream class

//using std::stoi()
string str="45";
int num = std::stoi(str);

//int to string

std::map<char,int>mymap;
//find
mymap['b']=20;
//an iterator to the element, if an element with specified key is found or map::end otherwise.
std::map<char,int>::iterator it = mymap.find('b');

//erase
mymap['c']=30;
mymap.erase('c');//erasing by key
it=mymap.find('e');
mymap.erase(it,mymap.end());//erasing by range

//loop through map
for(auto &kv:map){
	std::cout<<kv.first<<" has value "<<kv.second<<std::endl;
}

for(auto& [key,value]:map)

for(auto it=map.begin();it!=map.end();it++)

std::map<char,int> mymap;
mymap['a']=10;
mymap['b']=20;
mymap['c']=30;
mymap['d']=40;
mymap['e']=50;

auto il=mymap.lower_bound('b');  //il points to b
auto iu=mymap.upper_bound('d');  //iu points to e(not)