C++中的std :: minus

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)。

句法 ：

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

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

Member types :
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 
  
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());
  
    // 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  // std::cout
#include  // std::plus
#include  // 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());
  
    // Printing the result array
    for (int i = 0; i < 5; i++)
        std::cout << results[i] << " ";
  
    return 0;
}

输出：

90 180 270 360 450

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” 。