java - 为什么我不断收到错误: cannot find symbol for variables “weight” and “planet” ?

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);
}

由于某种原因无法识别变量 weight和 planet，并且基本上无法识别此代码中的所有其他变量。我以为这最初是扫描程序问题，但是在两种情况下都使用了 input.nextInt();，并且 input被声明为 Scanner。

Answer 1

至少在您发布的代码中未声明它们。

改成 :

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

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