add floaterr.c

chapter3/floaterr.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+int main()
+{
+	float a, b;
+	b = 2.0e20 + 1.0;
+	a = b - 2.0e20;
+	printf("a = %f\n", a);
+
+	return 0;
+}