为什么我一直收到错误：找不到变量的符号＆＃34; weight＆＃34;和＆＃34;星球＆＃34;？

Question

Scanner input = new Scanner(System.in);

System.out.println("Enter weight: ");
weight = input.nextInt();

System.out.println("Which planet: ");
planet = input.nextInt();

int venus = 1;
int mars = 2;
int jupiter = 3;
int saturn = 4;
int uranus = 5;
int neptune = 6;

if (planet == 1)
{
  venus_weight = weight * 0.78;
  System.out.println(+ venus_weight);
}
else if (planet == 2)
{
  mars_weight = weight * 0.39;
  System.out.println(+ mars_weight);
}
else if (planet == 3)
{
  jupiter_weight = weight * 2.56;
  System.out.println(+ jupiter_weight);
}
else if (planet == 4)
{
  saturn_weight = weight * 1.17;
  System.out.println(+ saturn_weight);
}
else if (planet == 5)
{
  uranus_weight = weight * 1.05;
  System.out.println(+ uranus_weight);
}
else
{
  neptune_weight = weight * 1.23;
  System.out.println(+ neptune_weight);
}

变量weight和planet由于某种原因而未被识别，基本上是此代码中的所有其他变量。我认为这最初是扫描程序问题，但在这两种情况下都使用了input.nextInt();，input被声明为Scanner。

Answer 1

至少在您发布的代码中，它们未被声明。

更改为：

System.out.println("Enter weight: ");
int weight = input.nextInt();

System.out.println("Which planet: ");
int planet = input.nextInt();