c++ max 比较最大值

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对于比较大小的方法，我们可以使用 algorithm下的函数，而不需要我们自己写函数。

1. 使用方法

#include <algorithm>
using namespace std;

 int a = 6, b = -7;
   // Return the integer with the larger absolute value
   const int& result1 = max(a, b, abs_greater);
   // Return the larger integer
   const int& result2 = max(a, b);

   cout << "Using integers 6 and -7..." << endl;
   cout << "The integer with the greater absolute value is: " 
        << result1 << "." << endl;
   cout << "The integer with the greater value is: " 
        << result2 << "." << endl;
   cout << endl;

// Comparing the members of an initializer_list
const int& result3 = max({ a, b });
const int& result4 = max({ a, b }, abs_greater);

cout << "Comparing the members of an initializer_list..." << endl;
cout << "The member with the greater value is: " << result3 << endl;
cout << "The integer with the greater absolute value is: " << result4 << endl;

2. 运行结果

Using integers 6 and -7...
The integer with the greater absolute value is: -7
The integer with the greater value is: 6.

Comparing the members of an initializer_list...
The member with the greater value is: 6
The integer wiht the greater absolute value is: -7

3. 详细解释

template<class Type>
    const Type& max(
        const Type& _Left, 
        const Type& _Right
    );
template<class Type, class Pr>
    const Type& max(
        const Type& _Left, 
        const Type& _Right,
        BinaryPredicate _Comp
    );


_Left 
The first of the two objects being compared.

_Right 
The second of the two objects being compared.

_Comp 
A binary predicate used to compare the two objects.

_IList 
The initializer list that contains the objects to be compared.