exp 11: init

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

11.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+
+double f(double x, double y) { return (y * y - x) / (y + x * y * y); };
+
+double rungen_kutta_4(double x0, double y0, double xn, int steps) {
+  double h = (xn - x0) / steps;
+
+  while (steps--) {
+    double k1 = f(x0, y0) * h;
+    double k2 = f(x0 + h / 2, y0 + k1 / 2) * h;
+    double k3 = f(x0 + h / 2, y0 + k2 / 2) * h;
+    double k4 = f(x0 + h, y0 + k3) * h;
+
+    double k = (k1 + k4 + 2 * (k2 + k3)) / 6;
+
+    x0 += h, y0 += k;
+  }
+
+  return y0;
+}
+
+int main() {
+  double x0 = 0, y0 = 5, xn = 1784;
+  int steps = 1000000;
+
+  printf("Value of y at x=%0.4lf is y=%0.4lf", xn,
+         rungen_kutta_4(x0, y0, xn, steps));
+}