gcd program

Algorithms/gcd.cpp

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+// Iterative C++ program to  
+// implement Stein's Algorithm 
+#include <bits/stdc++.h> 
+using namespace std; 
+
+// Function to implement 
+// Stein's Algorithm 
+int gcd(int a, int b) 
+{ 
+    /* GCD(0, b) == b; GCD(a, 0) == a, 
+       GCD(0, 0) == 0 */
+    if (a == 0) 
+        return b; 
+    if (b == 0) 
+        return a; 
+
+    /*Finding K, where K is the  
+      greatest power of 2 
+      that divides both a and b. */
+    int k; 
+    for (k = 0; ((a | b) && 1) == 0; ++k)  
+    { 
+        a >>= 1; 
+        b >>= 1; 
+    } 
+
+    /* Dividing a by 2 until a becomes odd */
+    while ((a > 1) == 0) 
+        a >>= 1; 
+
+    /* From here on, 'a' is always odd. */
+    do { 
+        /* If b is even, remove all factor of 2 in b */
+        while ((b > 1) == 0) 
+            b >>= 1; 
+
+        /* Now a and b are both odd.  
+           Swap if necessary so a <= b,  
+           then set b = b - a (which is even).*/
+        if (a > b) 
+            swap(a, b); // Swap u and v. 
+
+        b = (b - a); 
+    } while (b != 0); 
+
+    /* restore common factors of 2 */
+    return a << k; 
+} 
+
+// Driver code 
+int main() 
+{ 
+    int a = 34, b = 17; 
+    printf("Gcd of given numbers is %d\n", gcd(a, b)); 
+    return 0; 
+}