Merge branch 'main' of https://github.com/NMLT-NTTMK-K18/6-290-recursion

Bai001/Source.cpp

@@ -1,8 +1,24 @@
-#include <iostream>
+#include <iostream>;
+
 using namespace std;
 
+int Tong(int);
+
+int Tong(int n)
+{
+	if (n == 0)
+		return 0;
+	int s = Tong(n - 1);
+	return (s + n * n);
+}
+
 int main()
 {
+	int k;
+	cout << "Nhap n: ";
+	cin >> k;
 
-	return 0;
+	int kq = Tong(k);
+	cout << "S(" << k << ")= " << kq;
+	return 1;
 }

Bai006/Source.cpp

@@ -1,8 +1,21 @@
 #include <iostream>
+#include <iomanip>
 using namespace std;
 
+float Tong(int);
+
 int main()
 {
-
+	int n;
+	cout << "Nhap n: ";
+	cin >> n;
+	cout << "\nKet qua cua S(" << n << ") la:	" << setw(5) << setprecision(5) << Tong(n) << endl;
 	return 0;
+}
+
+float Tong(int n) {
+	if (n == 0) {
+		return 0;
+	}
+	return Tong(n - 1) + (float)n / (n + 1);
 }

Bai011/Source.cpp

@@ -1,8 +1,29 @@
 #include <iostream>
+#include <limits>
+#include <iomanip>
+#include <cmath>
 using namespace std;
 
+int sum(int);
+
 int main()
 {
+    int n;
+    cout << "\nEnter the value of n:        ";
+    cin >> n;
+    while (n > INT_MAX || n < 0)
+    {
+        cout << "The inputted value of n is invalid. Please re-enter the value of n." << endl;
+        cout << "\nEnter the value of n:        ";
+        cin >> n;
+    }
+    cout << "\nThe result of S(" << n << ") is:      " << sum(n) << "." << endl;
+    return 0;
+}
 
-	return 0;
+int sum(int n)
+{
+    if (n == 0)
+        return 0;
+    return (sum(n - 1) + pow(n,4));
 }

Bai016/Source.cpp

@@ -1,8 +1,21 @@
 #include <iostream>
 using namespace std;
 
+float Tong(int);
+
 int main()
 {
+	int k;
+	cout << "Nhap so nguyen: ";
+	cin >> k;
+	float kq = Tong(k);
+	cout << "Tong la: " << kq;
+	return 1;
+}
 
-	return 0;
+float Tong(int n)
+{
+	if (n == 0)
+		return 0;
+	return (Tong(n - 1) + (float)1 / (n * (n + 1) * (n + 2)));
 }

Bai021/Source.cpp

@@ -1,8 +1,23 @@
 #include <iostream>
 using namespace std;
 
+float Tong(float, int);
+
 int main()
 {
+	int k;
+	float y;
+	cout << "Nhap so nguyen: ";
+	cin >> k;
+	cin >> y;
+	float kq = Tong(y, k);
+	cout << "Ket qua la: " << kq;
+	return 1;
+}
 
-	return 0;
+float Tong(float x, int n)
+{
+	if (n == 0)
+		return x;
+	return (Tong(x, n - 1) * (x + n));
 }

Bai026/Source.cpp

@@ -1,8 +1,19 @@
-#include <iostream>
+#include<iostream>
+#include<cmath>
 using namespace std;
-
+float sum(int);
 int main()
 {
-
-	return 0;
+    int n;
+    cin >> n;
+    float kq = sum(n);
+    cout << kq;
+    return 0;
+
+}
+float sum(int n)
+{
+    if (n == 0)
+        return 0;
+    return sqrt(n + sum(n - 1));
 }

Bai031/Source.cpp

@@ -1,8 +1,23 @@
 #include <iostream>
+
 using namespace std;
 
+int TinhAn(int);
+
+int TinhAn(int n)
+{
+	if (n == 1)
+		return -2;
+	return 5 * TinhAn(n - 1) + 12;
+}
+
 int main()
 {
+	int k;
+	cout << "Nhap n: ";
+	cin >> k;
 
-	return 0;
+	int kq = TinhAn(k);
+	cout << "Ket qua la: " << kq;
+	return 1;
 }

Bai036/Source.cpp

@@ -1,8 +1,30 @@
 #include <iostream>
+#include <iomanip>
+#include <cmath>
 using namespace std;
 
+float Dem_so_le(int);
+
 int main()
 {
-
+	int n;
+	cout << "Nhap n: ";
+	cin >> n;
+	cout << "\nKet qua cua S(" << n << ") la:	" << setw(5) << setprecision(5) << Dem_so_le(n) << endl;
 	return 0;
+}
+
+float Dem_so_le(int n) {
+	n = abs(n);
+	if (n <= 9) {
+		if (n % 2 == 1) {
+			return 1;
+		}
+		return 0;
+	}
+	int dv = n % 10;
+	if (dv % 2 == 1) {
+		return Dem_so_le(n / 10) + 1;
+	}
+	return Dem_so_le(n / 10);
 }

Bai041/Source.cpp

@@ -1,8 +1,39 @@
 #include <iostream>
+#include <limits>
+#include <iomanip>
 using namespace std;
 
+bool EvenExisted(int);
+
 int main()
 {
+    int n;
+    cout << "\nEnter the value of n:           ";
+    cin >> n;
+    while (n > INT_MAX || n < 0)
+    {
+        cout << "The inputted value of n is invalid. Please re-enter the value of n." << endl;
+        cout << "\nEnter the value of n:        ";
+        cin >> n;
+    }
+    if (EvenExisted(n) == true)
+        cout << "\nIn the number " << n << " exists even digits." << endl;
+    else
+        cout << "\n In the number " << n << " doesn't exists even digits." << endl;
+    cout << endl;
+    return 0;
+}
 
-	return 0;
+bool EvenExisted(int n)
+{
+    n = abs(n);
+    if (n <= 9)
+    {
+        if (n % 2 == 0)
+            return true;
+        return false;
+    }
+    int unit = n % 10;
+    if (unit % 2 == 0)
+        return true;
 }

Bai046/Source.cpp

@@ -1,8 +1,26 @@
-#include <iostream>
+#include<iostream>
 using namespace std;
-
+long long a(int);
+long long b(int);
 int main()
 {
-
+	int n;
+	cin >> n;
+	long long kq = a(n);
+	long long kq2 = b(n);
+	cout << kq << " " << kq2;
 	return 0;
+}
+long long a(int n)
+{
+	if (n == 1)
+		return 2;
+	return 3 * b(n - 1) + 2 * a(n - 1);
+
+}
+long long b(int n)
+{
+	if (n == 1)
+		return 1;
+	return a(n - 1) + 3 * b(n - 1);
 }

Bai051/Source.cpp

@@ -1,8 +1,25 @@
 #include <iostream>
+#include <iomanip>
+#include <cmath>
 using namespace std;
 
+int S(int);
+
 int main()
 {
-
+	int n;
+	cout << "Nhap n: ";
+	cin >> n;
+	cout << "\nKet qua cua S(" << n << ") la:	" << setw(5) << S(n) << endl;
 	return 0;
+}
+
+int S(int n) {
+	if (n == 0) {
+		return 0;
+	}
+	if (n == 1) {
+		return 1;
+	}
+	return (1 + n) * S(n - 1) - n * S(n - 2);
 }

Bai056/Source.cpp

@@ -1,8 +1,32 @@
 #include <iostream>
+#include <limits>
+#include <iomanip>
 using namespace std;
 
+float sum(int);
+
 int main()
 {
+    int n;
+    cout << "\nEnter the value of n:        ";
+    cin >> n;
+    while (n > INT_MAX || n < 0)
+    {
+        cout << "The inputted value of n is invalid. Please re-enter the value of n." << endl;
+        cout << "\nEnter the value of n:        ";
+        cin >> n;
+    }
+    cout << "\nThe result of S(" << n << ") is:      " << setw(5) << setprecision(5) << sum(n) << "." << endl;
+    return 0;
+}
 
-	return 0;
+float sum(int n)
+{
+    if (n == 0)
+        return 0;
+    if (n == 1)
+        return 1;
+    float a = sum(n - 1);
+    float b = sum(n - 2);
+    return (a + (float)1 /(n + 1 / (a - b)));
 }