Golang invalid argument to INTN

One The problem background

          Recent projects , Because we have to deal with random problems , So use random numbers . The project is in the process of testing , Suddenly reported a mistake ：invalid argument to intn; The tips are as follows ：

Two The cause of the problem

          The random function I use here , yes golang Built in bag rand, The way to do it is rand.Intn, The input parameter of this method is a non negative number ; Then the return value is [0,n) Random number between ; When I use it , No input parameter n Judge , In some cases , Enter the reference n Will become 0, That is why the above error report ：invalid argument to intn
          in fact , This error is the prompt in the source code implementation of random functions ; When the passed in parameter is less than or equal to 0 when , You're going to throw this hint ; example demo as follows ：

package main

import (
	"fmt"
	"math/rand"