Day 13,14,15 (#158)

* day13 code and readme

* day14 code and readme

* day15 code and readme

day13/C++/factorialDay13.cpp

@@ -0,0 +1,25 @@
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int fact(int n){
+	if(n == 1) return 1;
+	else return n * fact(n - 1);
+}
+
+
+int main(){
+
+	int n;
+	cin >> n;
+
+	cout << "The factorial is " << fact(n);
+
+
+	return 0;
+}

day13/C++/fibonacciDay13.cpp

@@ -0,0 +1,30 @@
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int fibo(int n){
+	if(n <= 2) return 1;
+	else return fibo(n - 1) + fibo(n - 2);
+}
+int main(){
+
+	int n;
+	cin >> n;
+
+	cout << "The " << n << "th fibonacci number is " << fibo(n) << endl;
+
+	for(int i = 1; i <= n; i++){
+		if(i == n){
+			cout << fibo(i);
+		}
+		else{
+			cout << fibo(i) << " , ";
+		}
+	}
+	return 0;
+}

day13/README.md

@@ -115,6 +115,37 @@ int main()
 }
 ```
 
+#### [Solution](./C++/factorialDay13.cpp)
+
+```cpp
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int fact(int n){
+	if(n == 1) return 1;
+	else return n * fact(n - 1);
+}
+
+
+int main(){
+	
+	int n;
+	cin >> n;
+	
+	cout << "The factorial is " << fact(n);
+	
+	
+	return 0;
+}
+```
+
+
 ### C Implementation
 
 #### [Solution](./C/factorial.c)
@@ -423,6 +454,42 @@ int main()
 }
 ```
 
+#### [Solution](./C++/fibonacciDay13.cpp)
+
+```cpp
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int fibo(int n){
+	if(n <= 2) return 1;
+	else return fibo(n - 1) + fibo(n - 2);
+}
+int main(){
+	
+	int n;
+	cin >> n;
+	
+	cout << "The " << n << "th fibonacci number is " << fibo(n) << endl;
+	
+	for(int i = 1; i <= n; i++){
+		if(i == n){
+			cout << fibo(i);
+		}
+		else{
+			cout << fibo(i) << " , ";
+		}
+	}
+	return 0;
+}
+
+
+
 ### C Implementation
 
 #### [Solution](./C/fibonacci.c)

day14/C++/productDay14.cpp

@@ -0,0 +1,24 @@
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int product(int a, int b){
+	if(b == 0) return 0; // base case;
+	int ans = product(a, b/2);
+	if(b % 2 == 0) return 2 * ans;
+	else return 2 * ans + a;
+}
+int main(){
+	int num1, num2;
+	cin >> num1 >> num2;
+	int ans = product(num1, num2);
+	//since we are adding the first number in the recursive function, we get the ans only according to the num1, hence we need to adjust the sign accd to the num2.
+	if( (num2 < 0 && num1 > 0) || (num2 < 0 && num1 < 0)) ans *= -1;
+	cout << "The multiplication is " << ans;
+}

day14/C++/sumOfDigitsDay14.cpp

@@ -0,0 +1,20 @@
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int sum(int n){
+	if(n < 10) return n;
+	else return n % 10 + sum(n /10);
+}
+int main(){
+	int n;
+	cin >> n;
+	cout << "The sum of digits is " << sum(n);
+	return 0;
+}

day14/README.md

@@ -162,6 +162,30 @@ int main() {
 }
 ```
 
+#### [C++ Solution by @divyakhetan](./C++/sumOfDigitsDay14.cpp)
+```cpp
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int sum(int n){
+	if(n < 10) return n;
+	else return n % 10 + sum(n /10);
+}
+int main(){
+	int n;
+	cin >> n;
+	cout << "The sum of digits is " << sum(n);
+	return 0;
+}
+```
+
 ### Ruby Implementation
 
 #### [Solution](./Ruby/sum_of_digits.rb)
@@ -369,6 +393,30 @@ int main() {
 }
 ```
 
+#### [C++ Solution by @divyakhetan](./C++/productDay14.cpp)
+```cpp
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int sum(int n){
+	if(n < 10) return n;
+	else return n % 10 + sum(n /10);
+}
+int main(){
+	int n;
+	cin >> n;
+	cout << "The sum of digits is " << sum(n);
+	return 0;
+}
+```
+
 ### Ruby Implementation
 
 #### [Solution](./Ruby/product_of_two_numbers.rb)

day15/C++/pascalDay15.cpp

@@ -0,0 +1,27 @@
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+int pascal(int i, int j){
+	if(j == 1) return 1;
+	if(i == j ) return 1;
+	else return pascal(i - 1, j) + pascal(i - 1, j - 1);
+}
+
+int main(){
+	int n;
+	cin >> n;
+
+	for(int i = 1; i  <= n; i++){
+		for(int j = 1; j <= i; j++){
+			cout << pascal(i,j) << " ";
+		}
+		cout << endl;
+	}
+	return 0;
+}

day15/README.md

@@ -55,6 +55,33 @@ console.log ('\n/* ===== Pascal\'s Triangle for n = 7\n');
 printPascal (7);
 ```
 
+## C++ Implementation
+
+### [Solution](./C++/pascalDay15.cpp)
+
+```cpp
+/**
+ * @author:divyakhetan
+ * @date: 10/1/2019
+ */
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+
+int sum(int n){
+	if(n < 10) return n;
+	else return n % 10 + sum(n /10);
+}
+int main(){
+	int n;
+	cin >> n;
+	cout << "The sum of digits is " << sum(n);
+	return 0;
+}
+```
+
 ## Python Implementation
 
 ### [Solution] (./Python/pascal.py)