C++ unordered_multimap bucket_count()用法及代码示例

unordered_multimap::bucket_count()是C++ STL中的内置函数，该函数返回unordered_multimap容器中的存储桶总数。值区是容器内部哈希表中的一个插槽，根据其哈希值将元素分配给该插槽。

用法:

unordered_multimap_name.bucket_count()

参数：该函数不接受任何参数。

返回值：它返回一个无符号整数类型，表示桶的总数。

以下示例程序旨在说明上述函数：

示例1:

// C++ program to illustrate the 
// unordered_multimap::bucket_count()  
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
  
    // declaration 
    unordered_multimap<int, int> sample; 
  
    // inserts key and element 
    sample.insert({ 10, 100 }); 
    sample.insert({ 10, 100 }); 
    sample.insert({ 20, 200 }); 
    sample.insert({ 30, 300 }); 
    sample.insert({ 15, 150 }); 
  
    cout << "The total count of buckets: " 
         << sample.bucket_count(); 
  
    // prints all element bucket wise 
    for (int i = 0; i < sample.bucket_count(); i++) { 
  
        cout << "\nBucket " << i << ": "; 
  
        // if bucket is empty 
        if (sample.bucket_size(i) == 0) 
            cout << "empty"; 
  
        for (auto it = sample.cbegin(i);  
                  it != sample.cend(i); it++) 
            cout << "{" << it->first << ", " 
                 << it->second << "}, "; 
    } 
    return 0; 
}

输出：

The total count of buckets: 7
Bucket 0: empty
Bucket 1: {15, 150}, 
Bucket 2: {30, 300}, 
Bucket 3: {10, 100}, {10, 100}, 
Bucket 4: empty
Bucket 5: empty
Bucket 6: {20, 200},

示例2:

// C++ program to illustrate the 
// unordered_multimap::bucket_count()  
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
  
    // declaration 
    unordered_multimap<char, char> sample; 
  
    // inserts key and element 
    sample.insert({ 'a', 'b' }); 
    sample.insert({ 'a', 'b' }); 
    sample.insert({ 'b', 'c' }); 
    sample.insert({ 'r', 'a' }); 
    sample.insert({ 'c', 'b' }); 
  
    cout << "The total count of buckets: " 
         << sample.bucket_count(); 
  
    // prints all element bucket wise 
    for (int i = 0; i < sample.bucket_count(); i++) { 
  
        cout << "\nBucket " << i << ": "; 
  
        // if bucket is empty 
        if (sample.bucket_size(i) == 0) 
            cout << "empty"; 
  
        for (auto it = sample.cbegin(i);  
                    it != sample.cend(i); it++) 
            cout << "{" << it->first << ", " 
                 << it->second << "}, "; 
    } 
    return 0; 
}

输出：

The total count of buckets: 7
Bucket 0: {b, c}, 
Bucket 1: {c, b}, 
Bucket 2: {r, a}, 
Bucket 3: empty
Bucket 4: empty
Bucket 5: empty
Bucket 6: {a, b}, {a, b},

相关用法

注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 unordered_multimap bucket_count() function in C++ STL。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。