C++std::分区编译错误

C++ std::partition compile error

本文关键字：错误 编译 分区 C++std      更新时间：2023-10-16

我正在尝试对数组进行分区以进行快速排序。由于分区部分出现编译错误，我尚未对其进行完整编码。我不知道该如何看待错误列表。

这是加权点结构的标题

#ifndef WEIGHTED_POINT_H
#define WEIGHTED_POINT_H
struct WeightedPoint {
    _int64 pointWeight;
    int xCoordinate;
    int ycoordinate;
};
bool compareWeightedPoints(WeightedPoint p1, WeightedPoint p2);
#endif

这是它的CPP

#include "WeightedPoint.hpp"
bool compareWeightedPoints(WeightedPoint p1, WeightedPoint p2) {
    return p1.pointWeight < p2.pointWeight;
}

以下是的主要方法

#include <algorithm>
#include <vector>
#include "WeightedPoint.hpp"
const int VECTOR_SIZE = 100;
WeightedPoint* partitionWeightedPoints(WeightedPoint* first, WeightedPoint* last) {
    WeightedPoint* key = first;
    WeightedPoint* middle = std::partition(first + 1, last, [=](const WeightedPoint *data)->bool {return data->pointWeight < key->pointWeight; }) - 1;
}
void fillWeightedPointsVector(std::vector<WeightedPoint> inputData) {
    int counter = 0;
    while (counter++ < VECTOR_SIZE) {
        inputData.push_back({ std::rand(), std::rand(), std::rand() });
    }
}
int main() {
    std::vector<WeightedPoint> inputData;
    fillWeightedPointsVector(inputData);
    WeightedPoint* arrayToSort = inputData.data();
    int numberOfElements = inputData.size();
    partitionWeightedPoints(&arrayToSort[0], &arrayToSort[numberOfElements - 1]);
}

这是的编译错误

1>------ Build started: Project: TestPartition, Configuration: Debug Win32 ------
1>  WeightedPoint.cpp
1>  MainSource.cpp
1>c:program files (x86)microsoft visual studio 12.0vcincludealgorithm(2141): error C2664: 'bool partitionWeightedPoints::<lambda_a5c326daa6382dcb3f8cf628cbfa8999>::operator ()(const WeightedPoint *) const' : cannot convert argument 1 from 'WeightedPoint' to 'const WeightedPoint *'
1>          No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
1>          c:program files (x86)microsoft visual studio 12.0vcincludealgorithm(2164) : see reference to function template instantiation '_BidIt std::_Partition<_Iter,_Pr>(_BidIt,_BidIt,_Pr,std::bidirectional_iterator_tag)' being compiled
1>          with
1>          [
1>              _BidIt=WeightedPoint *
1>  ,            _Iter=WeightedPoint *
1>  ,            _Pr=partitionWeightedPoints::<lambda_a5c326daa6382dcb3f8cf628cbfa8999>
1>          ]
1>          c:usersgopalmenondocumentsvisual studio 2013projectstestpartitiontestpartitionmainsource.cpp(11) : see reference to function template instantiation '_FwdIt std::partition<WeightedPoint*,partitionWeightedPoints::<lambda_a5c326daa6382dcb3f8cf628cbfa8999>>(_FwdIt,_FwdIt,_Pr)' being compiled
1>          with
1>          [
1>              _FwdIt=WeightedPoint *
1>  ,            _Pr=partitionWeightedPoints::<lambda_a5c326daa6382dcb3f8cf628cbfa8999>
1>          ]
1>c:program files (x86)microsoft visual studio 12.0vcincludealgorithm(2146): error C2664: 'bool partitionWeightedPoints::<lambda_a5c326daa6382dcb3f8cf628cbfa8999>::operator ()(const WeightedPoint *) const' : cannot convert argument 1 from 'WeightedPoint' to 'const WeightedPoint *'
1>          No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
1>  Generating Code...
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

我不知道该怎么做。我不太擅长C++。任何帮助都将不胜感激。

std::partition希望谓词采用常量引用（即本例中的const WeightedPoint&），但谓词签名采用常量指针。这就是当前编译错误的来源。要删除它，例如更改

[=](const WeightedPoint *data)->bool {return data->pointWeight < key->pointWeight; }

至

[=](const WeightedPoint& data)->bool {return data.pointWeight < key->pointWeight; }
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