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C++ std::minus用法及代码示例


二进制函数对象类,其调用返回从其第一个参数减去第二个参数的结果(由二进制运算符-返回)。

用法:

template  struct minus:binary_function  
{
  T operator() (const T& x, const T& y) const {return x-y;}
};

模板参数:
T - Type of the arguments and return type of the functional call.
    The type shall support the operation (binary operator-).

成员类型:
x:Type of the first argument in member operator()
y:Type of the second argument in member operator()
result_type:Type returned by member operator()
// C++ program to illustrate std::minus 
// by subtracting all array elements from a number 
#include <bits/stdc++.h> 
  
int main() 
{ 
    // Array with elements to be subtracted 
    int arr[] = { 10, 20, 30 }; 
  
    // size of array 
    int size = sizeof(arr) / sizeof(arr[0]); 
  
    // Variable from which array is to be subtracted 
    int num = 100; 
  
    // Variable to store result 
    int result; 
  
    // using std::accumulate to perform subtraction on array from num 
    // using std::minus 
    result = std::accumulate(arr, arr + size, num, std::minus<int>()); 
  
    // Printing the result 
    std::cout << "The result of 100-10-20-30 is " << result; 
  
    return 0; 
}

输出:


The result of 100-10-20-30 is 40

另一个例子:

// C++ program to illustrate std::minus 
// by subtracting the respective elements of 2 arrays 
#include <iostream> // std::cout 
#include <functional> // std::plus 
#include <algorithm> // std::transform 
  
int main() 
{ 
    // First array 
    int first[] = { 100, 200, 300, 400, 500 }; 
  
    // Second array 
    int second[] = { 10, 20, 30, 40, 50 }; 
  
    // Result array 
    int results[5]; 
  
    // std::transform applies std::minus to the whole array 
    std::transform(first, first + 5, second, results, std::minus<int>()); 
  
    // Printing the result array 
    for (int i = 0; i < 5; i++) 
        std::cout << results[i] << " "; 
  
    return 0; 
}

输出:

90 180 270 360 450


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注:本文由纯净天空筛选整理自 std::minus 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。