獲取數組索引超出界限錯誤

Question

由於某種原因，我收到此錯誤。

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 7 
at Assignment25.main(Assignment25.java:80) 

public static void main (String[] args){ 
long[] array = new long[7]; 
for (int i = 0; i < 6; i++){ 
    int thefib = 39; 
    array[i] = fib(thefib); 
    thefib++; 
} 

int counter = 0; 
int counter1 = 1; 
for(int i = 0; i < 6; i++){ 
    long start = System.currentTimeMillis(); 
    gcd(array[counter], array[counter1]); 
    long end = System.currentTimeMillis(); 
    long time = end - start; 
    System.out.println("GCD time for " + (counter + 39) + " and " + (counter1 + 
     39) + " is " + time); 
    counter++; 
    counter1++; 
} 

counter = 0; 
counter = 1; 
for(int i = 0; i < 6; i++){ 
    long start1 = System.currentTimeMillis(); 
    gcd2(array[counter], array[counter1]); 
    long end1 = System.currentTimeMillis(); 
    long time1 = end1 - start1; 
    System.out.println("GCD2 time for " + (counter + 39) + " and " + (counter1 + 
     39) + " is " + time1); 
    counter++; 
    counter1++; 
    } 
} 

}

Answer 1

既然你開始你的counter1從1和for循環爲6迭代中，counter1在最後一次迭代這給ArrayIndexOutOfBoundsException變成7。因爲你array的大小爲7，且您嘗試使用array[counter1]時counter1變爲7

在陣列最大可訪問索引始終array.length - 1，你的情況來訪問索引7，array[6]是最後一個可訪問索引你的數組。

Answer 2

的counter1初始值是1和counter1值將是7通過i=6。但是沒有數組的索引。

Answer 3

陣列對於大小7定義和迭代僅進行6次......所以異常

Answer 4

當你增加counter和counter1，設置counter1爲counter1是準確counter+1。當counter是array.length-1時，您的counter1等於array.length即7。

正如你目的是計算兩個相鄰整數的GCD爲什麼不直接使用i本身：

for(int i = 0; i < array.length -1 ; i++){ // <<---- array.length-1 = 6, i guess 
    long start1 = System.currentTimeMillis(); 
    gcd2(array[i], array[i+1]); 
    // other code