MyArrayList myArrayList = new MyArrayList(); myArrayList.add(1); myArrayList.add(2); myArrayList.add(3); myArrayList.display(); /*myArrayList.add(5); myArrayList.display();*/ try{ myArrayList.add(1,99); }catch (AddIndexOutOfException e) { e.printStackTrace(); } myArrayList.display(); }怎么给他横着打印

您可以将 `MyArrayList` 类中的 `display()` 方法进行修改，改为横向打印元素。以下是一种可能的实现方式：

public void display() {
    if (size == 0) {
        System.out.println("[]");
        return;
    }
    System.out.print("[");
    for (int i = 0; i < size - 1; i++) {
        System.out.print(elementData[i] + ", ");
    }
    System.out.println(elementData[size - 1] + "]");
}

这个实现方式在打印元素时，首先输出一个左中括号 `[`，然后依次输出每个元素和一个逗号 `,`，最后输出一个右中括号 `]`。这样就能够横向打印元素了。

相关问题

将以下程序补充完整 #include <iostream> #include <fstream> #include <iomanip> using namespace std; template <typename ElemType> class myArrayList { private: int mSize; int mLen; ElemType *mpArr; public: myArrayList(int n); myArrayList(ElemType *a,int n); void show(); ElemType getMax(); //以下函数由同学完成 //void sort(); //myArrayList(myArrayList<ElemtType> &other);//拷贝构造函数 //mymyArrayList<ElemType> & operator =(mymyArrayList<ElemType> &other) }; template <typename ElemType> myArrayList<ElemType>::myArrayList(int n) { this->mSize=n; this->mLen=0; this->mpArr=new ElemType[mSize]; } template <typename ElemType> myArrayList<ElemType>::myArrayList(ElemType *a,int n) { this->mSize=n; this->mLen=n; this->mpArr=new ElemType[mSize]; for(int i=0;i<mLen;i++) mpArr[i]=a[i]; } template <typename ElemType> void myArrayList<ElemType>::show() { for(int i=0;i<mLen;i++) cout<<setw(4)<<mpArr[i]; cout<<endl; } template <typename ElemType> ElemType myArrayList<ElemType>::getMax() { ElemType max; max=mpArr[0]; for(int i=1;i<mLen;i++) if(max<mpArr[i]) max=mpArr[i]; return max; } //Student.h class Student { private: int mId; float height; int score; public: Student(int id=0,float h=0,int s=0):height(h),mId(id),score(s) { } friendbool operator <(Student &a1,Student &a2) { if(a1.height<a2.height) return true; else return false; } friend ostream &operator <<(ostream &out,Student &s) { out<<"ID:"<<s.mId<<" Height:"<<s.height<<" Socre:"<<s.score<<endl; return out; } }; //主程序 int main() { int a[]={1,2,3,5,7,9,12,8}; double b[]={1,2.5,3.6,5,7,9,12.8,8}; myArrayList <int> list1(a,8); list1.show(); cout<<"max="<<list1.getMax()<<endl; myArrayList <double> list2(b,8); list2.show(); cout<<"max="<<list2.getMax()<<endl; Student s[3]={Student(1,175,80),Student(2,178,90),Student(3,195,83)},s1; myArrayList <Student> list3(s,3); list3.show(); cout<<"max="<<list3.getMax()<<endl; } 说明： 将以下程序补充完整 //void sort(); //myArrayList(myArrayList<ElemtType> &other);//拷贝构造函数 //mymyArrayList<ElemType> operator =(mymyArrayList<ElemType> &other) //修改补充 Student类，要求按成绩排序（从高到低）

将以下程序补充完整：

template <typename ElemType> 
void myArrayList<ElemType>::sort() 
{
    for(int i=0; i<mLen-1; i++) 
    {
        for(int j=0; j<mLen-i-1; j++) 
        {
            if(mpArr[j] > mpArr[j+1]) 
            {
                ElemType temp = mpArr[j];
                mpArr[j] = mpArr[j+1];
                mpArr[j+1] = temp;
            }
        }
    }
}

template <typename ElemType>
myArrayList<ElemType>::myArrayList(myArrayList<ElemType> &other) 
{
    this->mSize = other.mSize;
    this->mLen = other.mLen;
    this->mpArr = new ElemType[mSize];
    for(int i=0; i<mLen; i++) 
    {
        mpArr[i] = other.mpArr[i];
    }
}

template <typename ElemType>
myArrayList<ElemType> & myArrayList<ElemType>::operator =(myArrayList<ElemType> &other) 
{
    if(this == &other)
        return *this;
    delete []mpArr;
    this->mSize = other.mSize;
    this->mLen = other.mLen;
    this->mpArr = new ElemType[mSize];
    for(int i=0; i<mLen; i++) 
    {
        mpArr[i] = other.mpArr[i];
    }
    return *this;
}

//修改补充 Student类，要求按成绩排序（从高到低）
class Student 
{
private:
    int mId;
    float height;
    int score;
public:
    Student(int id=0,float h=0,int s=0):height(h),mId(id),score(s) { }
    friend bool operator <(Student &a1,Student &a2) 
    {
        if(a1.score > a2.score) 
            return true;
        else 
            return false;
    }
    friend ostream &operator <<(ostream &out,Student &s) 
    {
        out<<"ID:"<<s.mId<<"  Height:"<<s.height<<"  Score:"<<s.score<<endl;
        return out;
    }
};

说明：

- `sort()`函数实现排序功能，采用冒泡排序算法；
- `myArrayList`类的拷贝构造函数和赋值运算符重载函数均实现深拷贝功能；
- `Student`类的 `<` 运算符重载函数改为按成绩从高到低排序。

public MyArrayList() { array = (T[]) new Object[10]; size = 0; }

这段代码是一个泛型类MyArrayList的构造函数。在构造函数中，首先创建了一个大小为10的Object类型的数组array，然后通过强制类型转换将其转换为一个泛型类型T的数组。最后将size初始化为0，表示当前列表中没有元素。由于Java中的泛型擦除机制，实际上在运行时，T将被替换为Object类型。