构建vi，使用labview固有函数计算用户输入的三个数的平均值。另外加一段代码，将平均值乘以0-1的一个随机数，将计算平均值的代码创建成子vi-Construction of vi, to use a labview inherent function to calculate the average of three numbers entered by the user. Also add a piece of code, the average value of a random num