Create pi.java

pi to 1000

pi.java

@@ -0,0 +1,34 @@
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+public class CalculatePi {
+    public static void main(String[] args) {
+        int scale = 1000;
+        BigDecimal pi = computePi(scale);
+        System.out.println(pi);
+    }
+
+    private static BigDecimal computePi(int scale) {
+        BigDecimal pi = BigDecimal.ZERO;
+        BigDecimal term1 = BigDecimal.ONE;
+        BigDecimal term2 = BigDecimal.ONE;
+        BigDecimal term3 = BigDecimal.ONE;
+        BigDecimal sign = BigDecimal.ONE;
+
+        for (int i = 0; i < scale; i++) {
+            BigDecimal divisor = new BigDecimal(2*i + 1);
+            term1 = term1.multiply(new BigDecimal(i * 2));
+            term2 = term2.multiply(new BigDecimal(i * 2 + 1));
+            term3 = term3.multiply(new BigDecimal(i * 2 + 2));
+            BigDecimal term = term1.multiply(term2).divide(term3.multiply(divisor), scale, RoundingMode.HALF_UP);
+
+            if (i % 2 == 0) {
+                pi = pi.add(term.multiply(sign));
+            } else {
+                pi = pi.subtract(term.multiply(sign));
+            }
+        }
+
+        return pi.multiply(new BigDecimal(2));
+    }
+}