This is my code in cpp

TANU SINGH/Fabonacci through Recursion.cpp

@@ -0,0 +1,20 @@
+#include <iostream>
+using namespace std;
+
+int fib (int n)
+{
+    if (n==0 || n==1)
+    return n;
+
+    else
+    return fib(n-1) + fib(n-2);
+}
+
+int main()
+{
+   int n;
+   cin>>n;
+   cout<<fib(n)<<endl;
+   return 0;
+}
+

TANU SINGH/Finding if array is sorted or not through Recursion.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+using namespace std;
+
+bool Sorted (int arr[], int n)
+{
+    if(n==1)
+    return true; 
+
+    else 
+    {
+    bool restarray = Sorted(arr+1, n-1);
+    return (arr[0]<arr[1] && restarray);
+    }
+}
+
+int main()
+{
+    int arr[] = {1,2,4,5};
+    cout<<Sorted(arr,4)<<endl;
+    return 0;
+}

TANU SINGH/First ans Last Occurence of a no in an array.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+using namespace std;
+
+int firstocc (int arr[], int n, int i, int key)
+{
+    if(i==n){
+    return -1;
+    }
+    if(arr[i] == key){
+    return i;
+    }
+
+    return firstocc (arr,n,i+1,key);
+}
+
+int lastocc (int arr[], int n, int i, int key)
+{
+    if(i==n){
+    return -1;
+    }
+
+    int restarr = lastocc(arr,n,i+1,key);
+    if (restarr!= -1)
+    return restarr;
+
+    if(arr[i]==key)
+    return i;
+
+    return -1;
+
+}
+
+int main()
+{
+
+   int arr[] = {5,6,7,7,8};
+   cout<<firstocc(arr,5,0,7)<<endl;
+   cout<<lastocc(arr,5,0,7)<<endl;
+   return 0;
+}
+

TANU SINGH/N strings and Q queries in each query you are given an string, print frequency of that string(unordered map).cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+   unordered_map <string, int>m;
+   int n;
+   cin>>n;
+
+   for(int i=0; i<n; i++){
+       string s;
+       cin>>s; 
+       m[s]++;
+   }
+
+   int q;
+   cin>>q;
+   while(q--){
+       string s;
+       cin>>s;
+       cout<<m[s]<<endl;
+   }
+
+    return 0;
+}

TANU SINGH/Sum of Subarrays.cpp

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+#include <iostream>
+using namespace std;
+
+int main()
+{
+   int n;
+   int sum = 0;                                           //stores the sum of the subarray
+   cout<<"enter the size of the array\n";
+   cin>>n;                                               //inputing the size of the array from the array
+   int A[n];
+   cout<<"Enter the elments of the array\n";
+
+   for(int i=0; i<n; i++)                                //loop for inputing the elements in the array
+   {
+      cin>>A[i]; 
+   }
+
+   for(int i=0; i<n; i++)                                 //loop to point to the starting 
+   { 
+       sum = 0;
+       for(int j=i; j<n; j++)                             //loop to point to the end point of the subarray
+       {
+        sum+= A[j];                                       //calculating the sum of the respective subarray     
+        cout<<"the sum of the subarray is "<<sum<<endl;   //printing the summ of the subarray
+       }
+   }
+    return 0;
+}

TANU SINGH/Tower_of_Hanoi.cpp

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+TOWER OF HANOI
+
+#include <iostream>
+using namespace std;
+
+void TowerOfHanoi(int n, char src, char dest, char help)
+{
+
+    if(n==0)
+    return;
+
+    TowerOfHanoi(n-1,src,help,dest);
+    cout<<"Move from "<<src<<" to "<<dest<<endl;
+    TowerOfHanoi(n-1,help,dest,src);
+}
+
+int main()
+{
+    TowerOfHanoi(3,'A','C','B');
+
+    return 0;
+}

TANU SINGH/print unique strings in lexographical order STL.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+    int n;
+    cin>>n;
+
+    map<string, int> m;
+
+    for(int i=0; i<n; i++){
+         string s;
+         cin>>s;
+         m[s]++;
+    }
+
+    for(auto pr:m){
+        cout<<pr.first<<" "<<pr.second<<endl;
+    }
+    return 0;
+}
+