C++ 中的向量，桶排序:分段错误 [英] Vectors in C++ , bucket sort : Segmentation fault

问题描述

在我的代码中，我试图实现桶排序，在我的实现中我尝试使用向量，但不幸的是我最终遇到了向量函数方面的错误.

In my code, I am trying to implement bucket sort and in my implementation I have tried using vectors, but unfortunately I end up with errors with respect to vector functions.

代码:

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

void bucket_sort(vector<float> & , int); //vector is passed by reference


int main(){

vector<float> array;
float element;
int count;


cout << "\nEnter the size of the vector : ";
cin >> count;

cout << "\nEnter the elements into the vector : ";

for(vector<float>::size_type i = 0 ; i < count ; i++){
    cin >> element;
    array[i].push_back(element);
}

bucket_sort(array , count);
}

void bucket_sort(vector<float> array, int count){

    vector<float> bucket;

    for(int i = 0 ; i < count ; i++){
        int bucket_index = count * array[i];
        bucket[bucket_index].push_back(array[i]);
    }

    for(int i = 0 ; i < count ; i++)
        sort(bucket[i].begin() , bucket[i].end());

    int index = 0;

    for(int i = 0 ; i < count ; i++)
        for(int j = 0 ; j < bucket[i].size() ; j++)
            array[index++].push_back(bucket[i][j]);
}

错误:

bucket_sort.cpp: In function ‘int main()’:
bucket_sort.cpp:24:12: error: request for member ‘push_back’ in ‘array.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(i)’, which is of non-class type ‘float’
   array[i].push_back(element);
            ^
bucket_sort.cpp: In function ‘void bucket_sort(std::vector<float>, int)’:
bucket_sort.cpp:36:24: error: request for member ‘push_back’ in ‘bucket.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(((std::vector<float>::size_type)bucket_index))’, which is of non-class type ‘float’
   bucket[bucket_index].push_back(array[i]);
                        ^
bucket_sort.cpp:40:18: error: request for member ‘begin’ in ‘bucket.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(((std::vector<float>::size_type)i))’, which is of non-class type ‘float’
   sort(bucket[i].begin() , bucket[i].end());
                  ^
bucket_sort.cpp:40:38: error: request for member ‘end’ in ‘bucket.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(((std::vector<float>::size_type)i))’, which is of non-class type ‘float’
   sort(bucket[i].begin() , bucket[i].end());
                                      ^
bucket_sort.cpp:45:33: error: request for member ‘size’ in ‘bucket.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(((std::vector<float>::size_type)i))’, which is of non-class type ‘float’
   for(int j = 0 ; j < bucket[i].size() ; j++)
                                 ^
bucket_sort.cpp:46:19: error: request for member ‘push_back’ in ‘array.std::vector<_Tp, _Alloc>::operator[]<float, std::allocator<float> >(((std::vector<float>::size_type)(index ++)))’, which is of non-class type ‘float’
    array[index++].push_back(bucket[i][j]);
                   ^
bucket_sort.cpp:46:40: error: invalid types ‘float[int]’ for array subscript
    array[index++].push_back(bucket[i][j]);

编辑代码:

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

void bucket_sort(vector<float> & , int); //vector is passed by reference


int main(){

vector<float> array;
float element;
int count;


cout << "\nEnter the size of the vector : ";
cin >> count;

cout << "\nEnter the elements into the vector : ";

for(int i = 0 ; i < count ; i++){
    cin >> element;
    array.push_back(element);
}

bucket_sort(array , count);

cout << "\nSorted vector : ";

for(int i = 0 ; i < count ; i++)
    cout << array[i] << " ";
 }

void bucket_sort(vector<float>& array, int count){

vector<float> bucket[count];

for(int i = 0 ; i < count ; i++){
    int bucket_index = count * array[i];
    bucket[bucket_index].push_back(array[i]);
}

for(int i = 0 ; i < count ; i++)
    sort(bucket[i].begin() , bucket[i].end());

int index = 0;

for(int i = 0 ; i < count ; i++)
    for(int j = 0 ; j < bucket[i].size() ; j++)
        array.push_back(bucket[i][j]);

}

我已经介绍了关于 push_back() 的更正，但现在在运行我的代码时，我遇到了分段错误.有什么建议吗?

Edit : I have introduced the correction with respect to the push_back() but now upon running my code I hit a segmentation fault. Any suggestions?

推荐答案

push_back 是 vector 的方法，而不是元素.要追加元素(向量大小增加 1)，请使用 array.push_back(123).给元素赋值使用 array[i] = 123.

push_back is method of vector, not element. To append element (with increasing vector size by 1) use array.push_back(123). To assign something to element use array[i] = 123.

如果你想用赋值来填充向量，你必须先调整向量的大小:array.resize(count).

If you want to fill vector using assignment, you have to resize vector first: array.resize(count).

要排序，写sort(array.begin() , array.end()).

bucket[i][j] 完全不正确:bucket 是一维向量.您可能希望 bucket 成为 vector>.

bucket[i][j] is totally incorrect: bucket is one dimensional vector. You probably want bucket to be vector<vector<float>>.

for(int i = 0 ; i < count ; i++){
    int bucket_index = count * array[i];
    bucket[bucket_index].push_back(array[i]);
}

您在 bucket 数组中只有 count 个元素，但要求 count * array[i] 元素.

You have only count elements in bucket array but ask for count * array[i] element.

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