std::equal()有助于将[first_1，last_1)范围内的元素与从first_2开始的范围内的元素进行比较。
语法1：
template
bool equal (InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2)
first_1, last_1:Initial and final positions of the first
sequence. All the elements are present within a range [first_1,last_1)
first2:Initial position of the second sequence.
返回：
true, if all of the elements in both ranges match; otherwise false
// C++ program illustrating
// use of bool equal (InputIterator1 first1, InputIterator1 last1,
// InputIterator2 first2)
#include <bits/stdc++.h>
int main()
{
int v1[] = { 10, 20, 30, 40, 50 };
std::vector<int> vector_1 (v1, v1 + sizeof(v1) / sizeof(int) );
// Printing vector1
std::cout << "Vector contains:";
for (unsigned int i = 0; i < vector_1.size(); i++)
std::cout << " " << vector_1[i];
std::cout << "\n";
// using std::equal()
// Comparison within default constructor
if ( std::equal (vector_1.begin(), vector_1.end(), v1) )
std::cout << "The contents of both sequences are equal.\n";
else
printf("The contents of both sequences differ.");
}输出：
Vector contains: 10, 20, 30, 40, 50 The contents of both sequences are equal.
语法2：
template
bool equal (InputIterator1 first1, InputIterator1 last1,
InputIterator2 first2, BinaryPredicate pred);
first_1, last_1:Initial and final positions of the first
sequence. All the elements are present within a range [first_1,last_1)
first2:Initial position of the second sequence.
pred:Binary function that accepts two elements as argument
and returns a value convertible to boolean.
返回：
true, if all of the elements in both ranges match; otherwise false
// C++ program illustrating
// use of bool equal (InputIterator1 first1, InputIterator1 last1,
// InputIterator2 first2, BinaryPredicate pred);
#include <bits/stdc++.h>
bool pred(int i, int j)
{
return (i != j);
}
int main()
{
int v1[] = { 10, 20, 30, 40, 50 };
std::vector<int> vector_1 (v1, v1 + sizeof(v1) / sizeof(int) );
// Printing vector1
std::cout << "Vector contains:";
for (unsigned int i = 0; i < vector_1.size(); i++)
std::cout << " " << vector_1[i];
std::cout << "\n";
// using std::equal()
// Comparison based on pred
if ( std::equal (vector_1.begin(), vector_1.end(), v1, pred) )
std::cout << "The contents of both sequences are equal.\n";
else
printf("The contents of both sequences differ.");
}输出：
Vector contains: 10, 20, 30, 40, 50 The contents of both sequences differ.
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注：本文由纯净天空筛选整理自 std::equal() in C++。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。