C++ SET,MAP DEMO

C++ SET,MAP DEMO.cpp

#include<bits/stdc++.h>
#include <iostream>
#include <set>
#include<map>
using namespace std;
void setDemo()
{
// In vectors we need to sort again and again after appending or updating values in order to perform lower and upper bounds (nlogn time)
// Set is better , every operation takes logn time.
set<int> S;
S.insert(1);S.insert(2);S.insert(-1);S.insert(12);
for(int x :S){cout<<x<<" ";} cout<<endl;    // -1 1 2 12
//TO check if an element exists in the set
auto it=S.find(-1); 
//if element does not exist iterator goes to s.end()
if(it==S.end()) { cout<<"not present\n";}
else { cout << *it <<" is present\n";}
//lowerbound->  >=  upperbound->   >
auto it2=S.lower_bound(-1);// In vectors we used .begin(),.end() because we use external fn lower_bound(),in sets it is internally present in the class
auto it3=S.lower_bound(0); // *it3 = 12 because zero is not present   
} 
void mapDemo()
{ //map means mapping somethting to something
    map<int,int> A;//mapping int to int
    A[1]=100;
    A[2]=-1;
    A[3]=300;
    A[100001]=1;
    map<char,int> cnt;
    string x="sudheer tripathi";
    for(char c:x)
    {
        cnt[c]++;
//we get the frequency of any character in the string
    }
    cout<<cnt['a']<<" "<<cnt['e']<<endl;
}
void PowerOfStl()
{
     
}
int main()
{
   setDemo();
   mapDemo();
   PowerOfStl();
   return 0;
}