爲什麼我的代碼導致ArrayIndexOutOfBoundsException？

Question

我想創建一個程序，根據用戶的輸入創建一個數組，用戶還可以輸入最大和最小數字。下面的代碼：

//Ask the user to enter the length of the array 
System.out.println("Please enter the length of the array: "); 
int arraylength = input.nextInt(); 

//Ask the user to enter a max value 
System.out.println("Please enter the max value: "); 
int max = input.nextInt(); 

//Ask the user to input the min value 
System.out.println("Please enter the min value: "); 
int min = input.nextInt(); 

//Initialize the array based on the user's input 
double [] userArray = new double[arraylength]; 


int range = (int)(Math.random() * max) + min; 

/** 
*The program comes up with random numbers based on the length 
*entered by the user. The numbers are limited to being between 
*0.0 and 100.0 
*/ 
for (int i = 0; i < userArray.length; i++) { 
    //Give the array the value of the range 
    userArray[arraylength] = range; 
    //Output variables 
    System.out.println(userArray[arraylength]); 
} 

這個問題似乎是與陣列的輸入的長度，在這一行：

userArray[arraylength] = range; 

我一直在尋找一個答案，但沒有拿出任何東西，任何幫助將非常感激。

Answer 1

你是對有問題的線路。這是

userArray[arraylength] = range; 

要明白髮生了什麼，你需要知道

• 數組的長度爲arraylength
• 數組元素編號/索引值從0到arraylength-1

像userArray[arraylength]這樣的調用會導致java.lang.ArrayIndexOutOfBoundsException，因爲您嘗試訪問索引6處的元素，而highes t允許值爲5.

Answer 2

該代碼塊包含錯誤;

for (int i = 0; i < userArray.length; i++) { 
    //Give the array the value of the range 
    userArray[arraylength] = range; 
    //Output variables 
    System.out.println(userArray[arraylength]); 
} 

您需要更改arraylength到i：

for (int i = 0; i < userArray.length; i++) { 
    //Give the array the value of the range 
    userArray[i] = range; 
    //Output variables 
    System.out.println(userArray[i]); 
}