技術標籤：# 4.1 C++c++stl標準庫equal

std::equal

簡介：
如果兩個序列的長度相同，並且對應元素都相等，equal() 演算法會返回 true。

函式原型

equality (1)	template <class InputIterator1, class InputIterator2>
  				bool equal (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
predicate (2)	template <class InputIterator1
 
, class InputIterator2, class BinaryPredicate>
  				bool equal (InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, BinaryPredicate pred);

官方手冊
http://www.cplusplus.com/reference/algorithm/equal/

使用示例：

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

using
 
 namespace std;

void Origin(vector<int>& v)
{
	v.push_back(1);
	v.push_back(2);
	v.push_back(3);
	v.push_back(4);
	v.push_back(5);
	v.push_back(6);
	v.push_back(7);
}

void Origin2(vector<int>& v)
{
	v.push_back(3);
	v.push_back(4);
	v.push_back(5);
	v.push_back(6);
	v.push_back
 
(7);
	v.push_back(8);
	v.push_back(9);
}

bool relationship(int e1, int e2)
{
	int tmp = e1 + 2;
	return  e2 == tmp;
}

void Print(vector<int>& v)
{
	vector<int>::iterator it;
	for (it = v.begin(); it != v.end(); it++)
		cout << *it << ",  ";
	cout << endl;
}

void main()
{
	vector<int> v1, v2;
	Origin(v1);
	Origin2(v2);

	cout << "vector v1: " << endl;
	Print(v1);
	cout << "vector v2: " << endl;
	Print(v2);

	bool eq = equal(v1.begin(), v1.end(), v2.begin());
	if (eq)
	{
		cout << "v1 == v2" << endl;
	}
	else
	{
		cout << "v1 != to v2" << endl;
	}

	bool eq2 = equal(v1.begin(), v1.end(), v2.begin(), relationship);
	if (eq2)
	{
		cout << "v2[i]==v1[i]+2" << endl;
	}
	else
	{
		cout << "v2[i]!=v1[i]+2" << endl;
	}
}