June 2018 Update

Task/Arithmetic-geometric-mean/C/arithmetic-geometric-mean-1.c

@@ -0,0 +1,32 @@
+#include<math.h>
+#include<stdio.h>
+#include<stdlib.h>
+
+double agm( double a, double g ) {
+   /* arithmetic-geometric mean */
+   double iota = 1.0E-16;
+   double a1, g1;
+
+   if( a*g < 0.0 ) {
+      printf( "arithmetic-geometric mean undefined when x*y<0\n" );
+      exit(1);
+   }
+
+   while( fabs(a-g)>iota ) {
+      a1 = (a + g) / 2.0;
+      g1 = sqrt(a * g);
+
+      a = a1;
+      g = g1;
+   }
+
+   return a;
+}
+
+int main( void ) {
+   double x, y;
+   printf( "Enter two numbers: " );
+   scanf( "%lf%lf", &x, &y );
+   printf( "The arithmetic-geometric mean is %lf\n", agm(x, y) );
+   return 0;
+}