在陣列上執行計算

Question

我有一個關於如何在數組上執行計算的問題。我將計算中的數組的長度用作存儲計算的數組的長度。在我的情況下，我所有的數組計算都很好，除了一個;它會顯示這個當我執行我的計劃：

run: 
Planets:    Mercury    Venus    Earth    Mars    Jupiter    Saturn    Uranus    Neptune    Pluto 
Radius:    2439.70    6051.90    6378.00    3402.50   71492.00   60270.00   25562.00   24774.00    1195.00 
Mass:    3.30e+23   4.87e+24   5.97e+24   6.42e+23   1.90e+27   5.68e+26   8.68e+25   1.02e+26   1.31e+22 
Gravity:     3.70    8.87    9.79     3.70    24.78    10.44    8.86    11.13    0.61 


3.7 
8.87 
9.79 
3.7 
24.78 
10.44 
8.86 
11.13 
0.61 
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 9 
at GravityV1.main(GravityV1.java:118) 
Java Result: 1 
BUILD SUCCESSFUL (total time: 0 seconds) 

這裏是我的代碼片段：

public class GravityV1 
{ 
// calcGravity returns an array of doubles containing teh gravity values 
//and takes two arrays of doubles as parameters for the radius values and mass 
public static double[] calcGravity(double[] radius, double[] mass) 
{ 
    // fill in code here 
     double[] grav = new double[radius.length]; 
     for(int i = 0; i < radius.length; i++){ 
      grav[i] = (6.67E-17) * mass[i]/Math.pow(radius[i], 2); 
     } 
     return grav; 
    // The formula to calculate gravity is: 
    // 6.67E-17 times the massOfPlanet divided by the radius of the planet squared 
} 
public static void main(String[] args)throws IOException 
{ 
    // Initialize variables 
    String[] names = {"Mercury", "Venus", "Earth", "Mars", "Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"}; 
    double[] radii = {2439.7, 6051.9, 6378, 3402.5, 71492, 60270, 25562, 24774, 1195}; 
    double[] masses = {3.3022 * Math.pow(10,23), 4.8685 * Math.pow(10,24), 5.9736 * Math.pow(10,24), 6.4185 * Math.pow(10,23), 
       1.8986 * Math.pow(10,27), 5.6846 * Math.pow(10,26), 8.6810 * Math.pow(10,25), 1.0243 * Math.pow(10,26), 1.312 * 
        Math.pow(10,22)}; 
// // calculate my weight on each planet 

      // declare & initialize my weight variable 
      double myWeight = 123.0; 

      // array for storage 
      double[] weight = new double[gravities.length]; 

      // for loop 
      for(i = 0; i < gravities.length; i++){ 
       weight[i] = myWeight * gravities[i]; 
      } 
      System.out.println(weight[i]); 

Answer 1

變化

for(i = 0; i < gravities.length; i++){ 
     weight[i] = myWeight * gravities[i]; 
} 
System.out.println(weight[i]); 

到

for(i = 0; i < gravities.length; i++){ 
     weight[i] = myWeight * gravities[i]; 
     System.out.println(weight[i]); 
}