JAVA-626: Added 3 articles

core-java-modules/core-java-lang-math/src/main/java/com/baeldung/algorithms/gcd/GCDImplementation.java

@@ -0,0 +1,55 @@
+package com.baeldung.algorithms.gcd;
+
+public class GCDImplementation {
+
+    public static int gcdByBruteForce(int n1, int n2) {
+        int gcd = 1;
+        for (int i = 1; i <= n1 && i <= n2; i++) {
+            if (n1 % i == 0 && n2 % i == 0) {
+                gcd = i;
+            }
+        }
+        return gcd;
+    }
+
+    public static int gcdByEuclidsAlgorithm(int n1, int n2) {
+        if (n2 == 0) {
+            return n1;
+        }
+        return gcdByEuclidsAlgorithm(n2, n1 % n2);
+    }
+
+    public static int gcdBySteinsAlgorithm(int n1, int n2) {
+        if (n1 == 0) {
+            return n2;
+        }
+
+        if (n2 == 0) {
+            return n1;
+        }
+
+        int n;
+        for (n = 0; ((n1 | n2) & 1) == 0; n++) {
+            n1 >>= 1;
+            n2 >>= 1;
+        }
+
+        while ((n1 & 1) == 0) {
+            n1 >>= 1;
+        }
+
+        do {
+            while ((n2 & 1) == 0) {
+                n2 >>= 1;
+            }
+
+            if (n1 > n2) {
+                int temp = n1;
+                n1 = n2;
+                n2 = temp;
+            }
+            n2 = (n2 - n1);
+        } while (n2 != 0);
+        return n1 << n;
+    }
+}

core-java-modules/core-java-lang-math/src/main/java/com/baeldung/algorithms/percentage/PercentageCalculator.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.percentage;
+
+import java.util.Scanner;
+
+public class PercentageCalculator {
+
+    public double calculatePercentage(double obtained,double total){
+        return obtained*100/total;
+    }
+
+    public static void main(String[] args) {
+        PercentageCalculator pc = new PercentageCalculator();
+        Scanner in = new Scanner(System.in);
+        System.out.println("Enter obtained marks:");
+        double obtained = in.nextDouble();
+        System.out.println("Enter total marks:");
+         double total =in.nextDouble();
+        System.out.println("Percentage obtained :"+pc.calculatePercentage(obtained,total));
+    }
+
+}