Java 数组索引HighArray和HighArrayApp？

将indexToDisplay设置为nothing实际上，您要做的是将其设置为find方法的返回值，如下所示：

int searchKey = 33; // search for item
int indexToDisplay = j
if( arr.find(searchKey) )
    System.out.println("Found " + searchKey + " at index: " + j );
else
    System.out.println("-1");

int indexToDisplay = arr.find(searchKey);

if(indexToDisplay != -1)
    System.out.println("Found " + searchKey + " at index: " + j );

public int find(long searchKey) 
{
    int j;
    for(j=0; j<nElems; j++) {  // for each element,
        if(a[j] == searchKey)     // found search value?
            return j;                // then exit loop before end (exits entire function)
    }
    // reached end of for loop
    return -1;             // thus, can't find it
} // end find()
public void insert(long value) 
{
    a[nElems] = value;
    nElems++; 
}

然后，由于find方法不返回布尔值，您可以执行如下检查以查看它是否是数组中的有效索引：

int searchKey = 33; // search for item
int indexToDisplay = j
if( arr.find(searchKey) )
    System.out.println("Found " + searchKey + " at index: " + j );
else
    System.out.println("-1");

int indexToDisplay = arr.find(searchKey);

if(indexToDisplay != -1)
    System.out.println("Found " + searchKey + " at index: " + j );

public int find(long searchKey) 
{
    int j;
    for(j=0; j<nElems; j++) {  // for each element,
        if(a[j] == searchKey)     // found search value?
            return j;                // then exit loop before end (exits entire function)
    }
    // reached end of for loop
    return -1;             // thus, can't find it
} // end find()
public void insert(long value) 
{
    a[nElems] = value;
    nElems++; 
}

我不确定nElems是什么，但是如果你在你的数组中找不到你想要的东西，我建议返回-1。所以我们总共有这样的东西：

int searchKey = 33; // search for item
int indexToDisplay = j
if( arr.find(searchKey) )
    System.out.println("Found " + searchKey + " at index: " + j );
else
    System.out.println("-1");

int indexToDisplay = arr.find(searchKey);

if(indexToDisplay != -1)
    System.out.println("Found " + searchKey + " at index: " + j );

public int find(long searchKey) 
{
    int j;
    for(j=0; j<nElems; j++) {  // for each element,
        if(a[j] == searchKey)     // found search value?
            return j;                // then exit loop before end (exits entire function)
    }
    // reached end of for loop
    return -1;             // thus, can't find it
} // end find()
public void insert(long value) 
{
    a[nElems] = value;
    nElems++; 
}

---

你为什么说如果arr.findsearchKey？这对于任何非零值都是正确的，除非我们考虑两种不同的方法。另外，你说你不能让它显示索引；它显示的是什么？错误的索引-1？现在的输出是什么？