使用高斯、复合梯形、复合辛普生求解二重积分（矩形求积区域和三角型求积区域）的数值计算方法，使用C语言。-Use Gaussian composite trapezoidal composite Simpson solving double integrals (Rectangular Quadrature region and the triangular the Quadrature area), numerical methods, the use of the C language.