C++ unordered_multimap max_load_factor()用法及代碼示例

unordered_multimap::max_load_factor()是C++ STL中的內置函數，該函數返回unordered_multimap容器的最大加載因子。此函數還提供設置最大負載係數的選項。

1. 用法(返回最大負載係數)：

   unordered_multimap_name.max_load_factor()

   參數：該函數不接受任何參數。

   返回值：它返回一個整數值，該值表示容器的最大負載係數。

   
   

   以下示例程序旨在說明上述函數：

   示例1:

   // C++ program to illustrate the 
   // unordered_multimap::max_size() 
   #include <bits/stdc++.h> 
   using namespace std; 
     
   int main() 
   { 
     
       // declaration 
       unordered_multimap<int, int> sample1; 
     
       // inserts key and element 
       // in sample1 
       sample1.insert({ 10, 100 }); 
       sample1.insert({ 50, 500 }); 
     
       // prints the max load factor 
       cout << "The max load factor  of sample1: "
            << sample1.max_load_factor(); 
     
       cout << "\nKey and Elements of Sample1 are:"; 
       for (auto it = sample1.begin(); it != sample1.end(); it++) { 
           cout << "{" << it->first << ", " << it->second << "} "; 
       } 
     
       return 0; 
   }

   輸出：

   The max load factor  of sample1: 1
   Key and Elements of Sample1 are:{50, 500} {10, 100}
   

2. 用法(設置最大負載係數)：

   unordered_multimap_name.max_load_factor(N)

   參數：該函數接受單個強製參數N，該參數指定要設置的負載係數。該N將是容器的最大負載係數。

   返回值：該函數不返回任何內容。

   以下示例程序旨在說明上述函數：

   // C++ program to illustrate the 
   // unordered_multimap::max_size() 
   #include <bits/stdc++.h> 
   using namespace std; 
     
   int main() 
   { 
     
       // declaration 
       unordered_multimap<int, int> sample1; 
     
       // inserts key and element 
       // in sample1 
       sample1.insert({ 10, 100 }); 
       sample1.insert({ 50, 500 }); 
     
       cout << "The max load factor of elements of sample1: "
            << sample1.max_load_factor(); 
     
       // sets the load factor 
       sample1.max_load_factor(100); 
     
       cout << "\nThe max load factor of sample1 after setting it: "
            << sample1.max_load_factor(); 
     
       cout << "\nKey and Elements of Sample1 are:"; 
       for (auto it = sample1.begin(); it != sample1.end(); it++) { 
           cout << "{" << it->first << ", " << it->second << "} "; 
       } 
     
       return 0; 
   }

   輸出：

   The max load factor of elements of sample1: 1
   The max load factor of sample1 after setting it: 100
   Key and Elements of Sample1 are:{50, 500} {10, 100}