Question

我对 C++ 中的 C++ 编程还很陌生，但我不断收到未声明变量和没有匹配函数调用的错误。主要目标是识别 x 和 y 变量之间的空间。

#include <iostream>

#include <math.h>

using namespace std;

struct Points
{
  float x, y;
};

float calcDistance(struct Point *num1, struct Point *num2)
{
float x_portion, y_portion

(x2 - x1)^2
x_portion = pow((num2->x - num1->x),2);

(y2 - y1)^2 
y_portion = pow((num2->y - num1->y),2);

return sqrt(x_portion, y_portion)
}

int main()
{
Point num1;
Point num2;
float calcDistance = 0;

cout << "Enter x and y coordinate for the first point: ";
cin >> num1.x >> num1.y;

cout << "Enter the x coordinate of the second point: ";
cin >> num2.x >> num2.y;

cout << "The distance between x and y is " << calcDistance(&num1, &num2) << endl;

return 0;

}

Answer 1

这是一个显示点并计算它们之间距离的代码片段：

struct Point2d
{
    float x;
    float y;

    float distance_to(const Point2d& other) const
    {
        const float x_dist = x - other.x;
        const float y_dist = y - other.y;
        const float x_squared = x_dist * x_dist;
        const float y_squared = y_dist * y_dist;
        return sqrt(x_squared + y_squared);
    }
};

你可以这样使用它：

Point2d a{3,4};
Point2d b{6,8};
float distance = a.distance_to(b);

您可能希望重载 operator- 而不是使用方法。

如果你不习惯结构中的方法，你可以让它独立：

float distance_between(const Point2d& a, const Point2d& b)
{
    const float x_dist = a.x - b.x;
    const float y_dist = a.y - b.y;
    const float x_squared = x_dist * x_dist;
    const float y_squared = y_dist * y_dist;
    return sqrt(x_squared + y_squared);
}

我更喜欢使用 const 临时变量，因为它允许调试器显示临时值。此外，编译器会优化它们（在更高的优化设置下）。

前向函数后定义变量时出错

1 个答案: