📜  C++ STL中的unordered_multimap key_eq()函数

📅  最后修改于: 2021-05-30 07:50:53             🧑  作者: Mango

unordered_multimap :: key_eq()是C++ STL中的内置函数,根据比较结果返回布尔值。它取决于unordered_multimap容器使用的键等效项比较谓词。密钥等效项比较是一个谓词,该谓词接受两个参数并返回一个布尔值,该布尔值指示它们是否被视为等效。如果它们相等则返回true,否则返回false。它在构造时由容器采用,类似于比较中使用的(==)运算符。

语法

unordered_multimap_name.key_eq()(args1, args2)

参数:该函数接受两个强制性参数args1args2 ,在这两个参数之间进行比较。 data_type与unordered_multimap的相同。

返回值:该函数返回一个布尔值。

下面的程序说明了unordered_multimap :: key_eq()函数:

程序1

// CPP program to illustrate the
// unordered_multimap::key_eq() function
  
#include 
#include 
#include 
  
using namespace std;
  
int main()
{
  
    unordered_multimap sample;
  
    bool answer = sample.key_eq()("GEEKS", "geeks");
  
    // checks if both are same
    if (answer)
        cout << "GEEKS and geeks are treated" << 
        " similarly in the container\n";
    else
        cout << "GEEKS and geeks are treated"
        << " dissimilarly in the container\n";
  
    return 0;
}
输出:
GEEKS and geeks are treated dissimilarly in the container

程序2

// CPP program to illustrate the
// unordered_multimap::key_eq() function
  
#include 
#include 
#include 
  
using namespace std;
  
int main()
{
  
    unordered_multimap sample;
  
    bool answer = sample.key_eq()(100, 200);
  
    // check
    if (answer)
        cout << "100 and 200 are treated "
         << "similarly in the container\n";
    else
        cout << "100 and 200 are treated"
        << " dissimilarly in the container\n";
  
    answer = sample.key_eq()(100, 100);
    if (answer)
        cout << "100 and 100 are treated "
        << "similarly in the container\n";
    else
        cout << "100 and 100 are treated "
        << "dissimilarly in the container\n";
  
    return 0;
}
输出:
100 and 200 are treated dissimilarly in the container
100 and 100 are treated similarly in the container
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