unordered_map

Author: geeky01adarsh

algorithm.cpp

@@ -4,11 +4,12 @@
 // Stores element in sorted order
 
 #include <iostream>
-#include<set>
+#include <set>
 
 using namespace std;
 
-int main(){
+int main()
+{
     // declaration
     set<int> s;
 
@@ -20,24 +21,24 @@ int main(){
     s.insert(5);
 
     // printing the set
-    set<int, greater<int> >::iterator itr;
+    set<int, greater<int>>::iterator itr;
     for (itr = s.begin(); itr != s.end(); itr++)
     {
-        cout <<*itr<<" ";
+        cout << *itr << " ";
     }
-    cout<<endl;
+    cout << endl;
 
     // finding any elements require O(log n)
     // "find" function returns the iterator in O(log n)
-    cout<<"Print 5 if present ";
-    cout<<*s.find(5)<<endl;
+    cout << "Print 5 if present ";
+    cout << *s.find(5) << endl;
     // "count" function returns bool value in O(log n) time
-    cout<<"Is 9 present in the set? "<<s.count(9)<<endl;
+    cout << "Is 9 present in the set? " << s.count(9) << endl;
 
     // deleting all elements in the set
-    cout<<"Is the set empty? "<<s.empty()<<endl;
+    cout << "Is the set empty? " << s.empty() << endl;
     s.clear();
-    cout<<"Is the set empty now? "<<s.empty()<<endl;
+    cout << "Is the set empty now? " << s.empty() << endl;
 
     return 0;
 }

set.cpp

@@ -0,0 +1,46 @@
+// stores in key-value pair
+// all kyes are not unique
+// not stored in sorted order
+
+#include <iostream>
+#include <unordered_map>
+
+using namespace std;
+
+int main(){
+    // declaration
+    unordered_map<int,string> um;
+
+    // assigning values
+    // m[key]=value
+    um[1]="Adarsh";
+    um[2]="Navneet";
+    um[30]="Sinha";
+
+    // inserting elements using insert function
+    um.insert({5,"geeky01adarsh"});
+
+    // printing the map
+    for(auto i:um){
+        cout<<"key = "<<i.first<<" and its value = "<<i.second<<endl;
+    }
+    cout<<endl;
+
+    // to check if an element is present or not(time-- O(1))
+    cout<<"Is 13 present in map? "<<um.count(13)<<endl;
+
+    // to return iterator where any element is present(time-- O(1))
+    um.find(1);
+    
+    // deleting any key-value pair
+    // takes key name as argument
+    um.erase(2);
+    // checking the map
+    for(auto i:um){
+        cout<<"key = "<<i.first<<" and its value = "<<i.second<<endl;
+    }
+    cout<<endl;
+
+
+    return 0;
+}