added questions using recursion

C++/LeapYearORNot.cpp

@@ -0,0 +1,24 @@
+#include<iostream>
+using namespace std;
+
+void leapYear(int year)
+{
+    if((year % 4 == 0 && year % 100 != 0 ) || (year % 400 == 0))
+    {
+        cout<<"Yes it's a leap year"<<endl;
+    }
+    else
+    {
+        cout<<"No it's not a leap year"<<endl;
+    }
+
+}
+int main()
+{
+    int year;
+    cin>>year;
+    {
+        leapYear(year);
+    }
+    return 0;
+}

C++/Questions using Recursion/checkPalindrome.cpp

@@ -0,0 +1,33 @@
+#include <iostream>
+#include <cstring>
+using namespace std;
+
+bool isPalRec(char input[],int s,int e)
+{
+    if(s==e)
+        return true;
+    if(input[s]!=input[e])
+        return false;
+    if(s<e+1)
+    return isPalRec(input,s+1,e-1);
+    return true;
+}
+bool checkPalindrome(char input[]) {   
+    int n=strlen(input);
+    if(n==0)
+        return true;
+    return isPalRec(input,0,n-1);    
+}
+int main() {
+    char input[50];
+    cin >> input;
+
+    if(checkPalindrome(input)) {
+        cout << "true" << endl;
+    }
+    else {
+        cout << "false" << endl;
+    }
+}
+
+

C++/Questions using Recursion/countZeroes.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    int n;
+    cin >> n;
+    cout << countZeros(n) << endl;
+}
+
+int countZeros(int n) {
+    // Write your code here
+    if(n==0)
+        return 1;
+    if(n<10)
+        return 0;
+    else if(n%10==0)
+        return 1+countZeros(n/10);
+    return countZeros(n/10);
+}
+
+

C++/Questions using Recursion/firstIndexOfNumber.cpp

@@ -0,0 +1,41 @@
+#include<iostream>
+using namespace std;
+
+int firstIndex(int input[], int size, int x) {
+    if(size==1){
+       if(input[0]==x)
+           return 0;
+       else
+           return -1;
+    }
+
+    if(input[0]==x)
+        return 0;
+    else{
+    int index=firstIndex(input+1,size-1,x);
+        if(index != -1) 
+            return index+1;
+        else
+            return -1;
+    }
+
+}
+int main(){
+    int n;
+    cin >> n;
+
+    int *input = new int[n];
+
+    for(int i = 0; i < n; i++) {
+        cin >> input[i];
+    }
+
+    int x;
+
+    cin >> x;
+
+    cout << firstIndex(input, n, x) << endl;
+
+}
+
+

C++/Questions using Recursion/geometricSum.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <math.h>
+#include <iomanip>
+using namespace std;
+
+int main() {
+    int k;
+    cin >> k;
+    cout << fixed << setprecision(5);
+    cout << geometricSum(k) << endl;   
+}
+
+double geometricSum(int k) {
+    // Write your code here
+    if(k==0)
+        return 1;
+    double ans = 1 / (double)pow(2, k) + geometricSum(k - 1); 
+    return ans;
+}
+
+

C++/Questions using Recursion/multiplication.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+using namespace std;
+
+int multiplyNumbers(int m, int n) {
+    // Write your code here
+    if(m==0)
+    {
+        return 0;
+    }
+    int result=(m*n);
+    return result;
+}
+int main() {
+    int m, n;
+    cin >> m >> n;
+    cout << multiplyNumbers(m, n) << endl;
+}

C++/Questions using Recursion/removeX.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+using namespace std;
+
+void removeX(char input[]) {
+    // Write your code here
+    if(input[0]=='\0')
+        return;
+    if(input[0]=='x'){
+        int i=1;
+        for(;input[i]!='\0';i++)
+            input[i-1]=input[i];
+        input[i-1]=input[i];
+        removeX(input);
+    }
+    removeX(input+1);
+}
+int main() {
+    char input[100];
+    cin.getline(input, 100);
+    removeX(input);
+    cout << input << endl;
+}
+

C++/Questions using Recursion/replacePi.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <cstring>
+using namespace std;
+
+void replacePi(char input[]) {
+	// Write your code here
+    if(input[0]=='\0')
+        return;
+    if(input[0]=='p' && input[1]=='i')
+    {
+        input[0]='3';
+        input[1]='.';
+
+        int size=strlen(input);
+        for(int i=size+2;i>1;i--)
+        {
+            input[i]=input[i-2];
+        }
+        input[2]='1';
+        input[3]='4';
+    }
+    replacePi(input+1);
+}
+int main() {
+    char input[10000];
+    cin.getline(input, 10000);
+    replacePi(input);
+    cout << input << endl;
+}
+

C++/Questions using Recursion/stringToInteger.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+#include<cmath>
+#include<cstring>
+using namespace std;
+
+int stringToNumber(char input[]) {
+    // Write your code her
+    if (input[0]=='\0')
+        return 0;
+    int ans=stringToNumber(input+1);
+
+    int size=strlen(input);
+    int d=(input[0]-48)*pow(10,size-1);
+    return ans+d;
+
+}
+
+int main() {
+    char input[50];
+    cin >> input;
+    cout << stringToNumber(input) << endl;
+}