Question

我需要帮助！我正在做一个结构数组的堆，我的reheap down算法似乎是错误的，我已经尝试了所有我知道的东西，这种东西在没有结构，只有数组时有效。所以这是错误：

main.cpp: In function 'void reheapDown(hitna**, int, int&)':
main.cpp:88: error: invalid types 'hitna**[std::ios_base& ()(std::ios_base&)]' for array subscript
main.cpp:89: error: invalid conversion from 'std::ios_base& (*)(std::ios_base&)' to 'int'

和代码：

#include <iostream>
#include <vector>
#include <string>

using namespace std;

struct hitna{
    string ime;
    int broj;
};

void unos(hitna *heap[50], int &last);
void reheapUp(hitna *heap[], int &last);
void exchange(hitna *&x, hitna *&y);
void reheapDown(hitna *heap[],int parent,  int &last);
void obrada(hitna *heap[], int &last);

int main(){

hitna *heap[50]={0};
int last = -1;
int odg;
do{
    cout<<"- - - I Z B O R N I K - - -";
    cout<<"\n\n1)Unos pacijenata\n";
    cout<<"2)Obrada pacijenata\n";
    cout<<"3)Ispis pacijenata\n";
    cout<<"4)Izlaz\n";

    cout<<"\nOdabir: ";
    cin>>odg;

    switch(odg){
        case 1:          
           unos(heap, last);
            break;
        case 2: 
            obrada(heap, last);
        break;
        case 3:
            for (int i=0;i<=last;i++){
                cout<<heap[i]->ime<<" "<<heap[i]->broj<<endl;
            }
        case 4:break;
        default:
            break;

    };
}while(odg!=4);

return 0;
}

void exchange(hitna *&x, hitna *&y){
    hitna *t = x;
    x=y;
    y=t;

}

void unos(hitna *heap[50], int &last){
    last++;
    heap[last]=new hitna;
    cout<<"IME: ";cin>>heap[last]->ime;
    cout<<"BROJ: ";cin>>heap[last]->broj;

    reheapUp(heap, last);


}
void reheapUp(hitna *heap[], int &last){
    int parent=(last-1)/2;
    if (heap[parent]->broj < heap[last]->broj){
        exchange(heap[parent], heap[last]);
        reheapUp(heap, parent);}

}  



void reheapDown(hitna *heap[],int parent, int &last){
int left = 2 * parent + 1;

if(left<=last){
    int child = left;
    if(left+1<=last) int right = child+1;

    if ((heap[right]->broj) > (heap[left]->broj)) //THIS IS WRONG
            {child = right;}                        //THIS ALSO

    if (heap[parent]->broj < heap[child]->broj){
        exchange(heap[parent], heap[child]);
        reheapDown(heap, child, last);

    }
}

}

void obrada(hitna *heap[], int &last){
    if(last<0) {return;}
    exchange(heap[0], heap[last]);
    last--;
    reheapDown(heap, 0, last);
}

Answer 1

right的范围不正确。

if(left+1<=last) int right = child+1;

标识符right仅存在于此if块中，因此您无法在外部使用它。在这种情况下，您需要确定哪些是正确的。如果条件left+1<=last不成立，您是否仍应执行函数中的剩余代码？如果是这样，您需要在right之外声明（与left相同的范围级别），并为其指定适当的值。

我希望你想要这样的东西：

if(left+1 <= last) {
    int child = left;
    int right = left+1;

    if ((heap[right]->broj) > (heap[left]->broj))
        child = right;

    if (heap[parent]->broj < heap[child]->broj) {
        exchange(heap[parent], heap[child]);
        reheapDown(heap, child, last);
    }
}

数组下标c ++（HEAP）

1 个答案: