本例中用c语言编写一个简单的BP神经网络，并用这个网络对正正弦函数SIN(X)在（0,1）段部分进行拟合，适合初学者。-This example uses a simple c language BP neural network, and uses this network is the sine function SIN (X) in (0,1) segment part of the fitting, suitable for beginners.