猜谜活动

猜谜活动。

人生艰难，听来个谜语给大家讲讲，娱乐一下。

话说某同学整了以下C++代码，运行就崩溃。

问：为啥？

等级考试以后公布答案。

#include<iostream>

using namespace std;

struct heap{

private:

int *root;

int heapSize;

int maxSize;

void build_Heap(){

int n = (heapSize+1)/2 -1;

for(int i = n;i>=0;i--){

max_Heapify(i);

}

}

public:

heap(int *a,int size){

heap(20);

cout<<"hhh";

for(int i = 0;i<size;i++){

root[i] = a[i];

}

heapSize = size;

build_Heap();

}

heap(int maxSize){

root = new int [maxSize];

}

heap(){

root = new int [20];

}

void copyBuild(int *a,int size){

cout<<"hhh";

for(int i = 0;i<size;i++){

root[i] = a[i];

}

heapSize = size;

build_Heap();

}

void max_Heapify(int i){

int leftChild = i*2+1;

int rightChild = i*2+2;

int max = root[i];

int maxLoc = i;

if(leftChild<heapSize&&root[leftChild]>max){

max = root[leftChild];

maxLoc = leftChild;

}

if(rightChild<heapSize&&root[rightChild]>max){

max = root[rightChild];

maxLoc = rightChild;

}

if(maxLoc!=i){

root[maxLoc] = root[i];

root[i] = max;

max_Heapify(maxLoc);

}

}

int pop_top(){

if(0==heapSize){

cout<<"error!!! this is an empty heap\n";

return -9999999;

}

if(1==heapSize){

heapSize = heapSize-1;

return root[0];

}

else {

int max = root[0];

root[0] = root[--heapSize];

max_Heapify(0);

return max;

}

}

void output(){

for(int i = 0;i<heapSize;i++){

cout<<root[i]<<" ";

if((i+1)%10==0) cout<<endl;

}

cout<<endl;

}

};

int main(){

int *a = new int [20];

for(int i = 0;i<9;i++){

a[i] = i;

cout<<a[i]<<" ";

}

int ss = 9;

heap *p = new heap(a,9);

cout<<"build heap\n";

p->output();

cout<<"pop_top "<<p->pop_top()<<endl;

}