【C++ Primer Plus习题】7.10

问题:

解答:

#include <iostream>
using namespace std;

double add(double a, double b)
{
	return a + b;
}

double mul(double a, double b)
{
	return a * b;
}

double sub(double a, double b)
{
	return a - b;
}

double div(double a, double b)
{
	return a / b;
}

double calculate(double num1, double num2, double (*p)(double, double))
{
	return p(num1, num2);
}

int main()
{
	double num1 = 0.0;
	double num2 = 0.0;
	double res = 0.0;
	
	cout << "请输入第1个数值:";
	cin >> num1;
	cout << "请输入第2个数值:";
	cin >> num2;
	res = calculate(num1, num2, add);
	cout << num1 << "+" << num2 << "=" << res << endl;
	res = calculate(num1, num2, mul);
	cout << num1 << "*" << num2 << "=" << res << endl;
	

	double (*p[4])(double, double);
	double result[4];
	p[0] = &add;
	p[1] = &mul;
	p[2] = &sub;
	p[3] = &div;
	for (int i = 0; i < 4; i++)
	{
		result[i] = calculate(num1, num2, p[i]);
	}
	cout << endl;
	cout << num1 << "+" << num2 << "=" << result[0]<< endl;
	cout << num1 << "-" << num2 << "=" << result[2] << endl;
	cout << num1 << "*" << num2 << "=" << result[1] << endl;
	cout << num1 << "/" << num2 << "=" << result[3] << endl;


	return 0;
}

运行结果:

考查点:

• 函数指针
• 指针数组

注意:

• 函数指针的定义

  

• 函数指针数组定义
  

• 函数指针的指向
  

2024年8月31日21:03:20