unordered_multimap :: hash_function()是C++ STL中的内置函数,用于获取哈希函数。该哈希函数是一元函数,仅接受单个参数,并基于该参数返回一个唯一的大小为size_t的值。
语法:
unordered_multimap_name.hash_function()
参数:该函数不接受任何参数。
返回值:该函数返回哈希函数。
下面的程序说明了unordered_multimap :: hash_function()函数:
程序1 :
// C++ program to illustrate the
// unordered_multimap::hash_function()
#include
#include
using namespace std;
int main()
{
// declaration
unordered_multimap sample;
// inserts key and elements
sample.insert({ "gopal", "dave" });
sample.insert({ "gopal", "dave" });
sample.insert({ "gopal", "dave" });
sample.insert({ "geeks", "geeks" });
// use of hash_function
unordered_multimap::hasher fn
= sample.hash_function();
cout << fn("geeks") << endl;
// print the key and elements
cout << "Key and Elements: ";
for (auto it = sample.begin(); it != sample.end(); it++) {
cout << "{" << it->first << ":"
<< it->second << "}, ";
}
return 0;
}
输出:
15276750567035005396
Key and Elements: {geeks:geeks}, {gopal:dave}, {gopal:dave}, {gopal:dave},
程序2 :
// C++ program to illustrate the
// unordered_multimap::hash_function()
#include
#include
using namespace std;
int main()
{
// declaration
unordered_multimap sample;
// insertion of key and elements
sample.insert({ "gopal", "dave" });
sample.insert({ "geeks", "geeks" });
// use of hash_function
unordered_multimap::hasher fn
= sample.hash_function();
cout << fn("geeksforgeeks") << endl;
// print the key and elements
cout << "Key and Elements: ";
for (auto it = sample.begin(); it != sample.end(); it++) {
cout << "{" << it->first << ":"
<< it->second << "}, ";
}
return 0;
}
输出:
5146686323530302118
Key and Elements: {geeks:geeks}, {gopal:dave},
要从最佳影片策划和实践问题去学习,检查了C++基础课程为基础,以先进的C++和C++ STL课程基础加上STL。要完成从学习语言到DS Algo等的更多准备工作,请参阅“完整面试准备课程” 。