import java.awt.*; import java.awt.image.*; public class trapezoidal extends integrator { public trapezoidal(double x[], double y[], int nint) { value = 0; int ppi = (x.length - 1) / nint; for (int i = 0; i < nint; i ++) { int j1 = i * ppi; int j2 = (i + 1) * ppi; double dv = (x[j2] - x[j1]) * (y[j2] + y[j1]) / 2.0; value += dv; } } }