Question

我已经生成了一个随机数组，我需要一种方法来返回用户输入值的索引。因此，如果它给出8个随机数，则它会要求用户在数组中找到一个值。一旦输入该值，它就需要返回该值的第一个索引。我们在课堂上没有这么多，我不知道最好的方法。这就是我到目前为止所拥有的：

Scanner input = new Scanner(System.in);
System.out.println("Enter an integer to find in the array:");
int target = input.nextInt();

// Find the index of target in the generated array.

/*
** 3. write findValue **
*/
int index = findValue(array, target);


if (index == -1)
{
    // target was not found
    System.out.println("value " + target + " not found");
}
else
{
    // target was found
    System.out.println("value " + target + " found at index " + index);
}

}


/*
  allocate a random int[] array with size elements, fill with
  random values between 0 and 100
*/

public static int[] generateRandomArray(int size)
{
// this is the array we are going to fill up with random stuff
int[] rval = new int[size];

Random rand = new Random();

for (int i=0; i<rval.length; i++)
{
    rval[i] = rand.nextInt(100);
}

return rval;
}


/*
  print out the contents of array on one line,  separated by delim
*/
public static void printArray(int[] array, String delim)
{

// your code goes here
    System.out.println (Arrays.toString(array));
}


/*
  return the count of values in array that are not divisible evenly by 2
*/
public static int countOdds(int[] array)
{
int count=0;

// your code goes here
    for (int i=0; i<array.length; i++){
        if (array[i] %2 !=0) {
            count++;

        }
    }


return count;
}


/*
  return the first index of value in array.  Return -1 if value is not present.
*/
public static int findValue(int[] array, int value)
{
// your code goes here


return -1;

}


}

Answer 1

首先，请修正您的问题标题。

现在解决方案。你会如何在现实生活中做到这一点？如果匹配搜索到的值，您将遍历数组并检查每个条目。这就是你如何用Java做到这一点。

public static int findValue(int[] array, int value) {
    for (int i = 0; i < array.length; i++) { // iterate over the content of the given array
        if (array[i] == value) { // check if the current entry matches the searched value
            return i; // if it does return the index of the entry
        }
    }
    return -1; // value not found, return -1
}

以下是调用此方法的示例：

public static void main(String[] args) {
    int[] array = new int[] { 1, 2, 3, 4, 5, 6 };
    System.out.println(findValue(array, 6));
}

这将打印5，因为数字6位于给定数组中的第5个位置。请注意，索引以0开头。

返回数组中的值的数量不能均匀地除2

1 个答案: