C 中使用结构的点积和叉积

Question

我必须创建一个包含 x、y 和 z 的结构 vector3d
然后我必须创建两个 struct vector 3d 类型的变量并在其中存储两个向量
接下来，我必须编写一个函数来计算这两个向量的点积和叉积。需要哪种 return 类型？

这就是我到目前为止所拥有的。也许有人可以帮助我。

#include <stdio.h>
#include <stdlib.h>

int n = 3;

struct vector3d
{
    int x, y, z;
};

int dot_product (int v1[], int v2[], int n)
{
    int dproduct = 0;
    n = 3;
    
    for(int i = 0; i < n; i++)
        dproduct += v1[i] * v2[i];
    return dproduct;
}

void cross_product (int v1[], int v2[], int crossproduct[])
{
    crossproduct[0] = v1[1] * v2[2] - v1[2] * v2[1];
    crossproduct[1] = v1[0] * v2[2] - v1[2] * v2[0];
    crossproduct[2] = v1[0] * v2[1] - v1[1] * v2[0];
}

int main()
{
    struct vector3d v1 = {0,0,0};
    struct vector3d v2 = {0,0,0};
    
    printf("Vector 1 - Enter value for x: ");
    scanf("%d", &v1.x);
    printf("Vector 1 - Enter value for y: ");
    scanf("%d", &v1.y);
    printf("Vector 1 - Enter value for z: ");
    scanf("%d", &v1.z);
    
    printf("Vector 2 - Enter value for x: ");
    scanf("%d", &v2.x);
    printf("Vector 2 - Enter value for y: ");
    scanf("%d", &v2.y);
    printf("Vector 2 - Enter value for z: ");
    scanf("%d", &v2.z);
}

Answer 1

您不能使用 int[] 代替 vector3d。您可以传递矢量结构并使用它来执行您的任务。这段代码我已经写好了，大家可以根据需要修改。

#include <stdio.h>
#include <stdlib.h>

int n = 3;

typedef struct vector3d
{
    int x, y, z;
} vector3d;

int dot_product(vector3d v1, vector3d v2)
{
    int dproduct = 0;

    dproduct += v1.x * v2.x;
    dproduct += v1.y * v2.y;
    dproduct += v1.z * v2.z;
    return dproduct;
}

vector3d cross_product(vector3d v1, vector3d v2)
{
    vector3d crossproduct = {0, 0, 0};
    crossproduct.x = v1.y * v2.z - v1.z * v2.y;
    crossproduct.y = v1.x * v2.z - v1.z * v2.x;
    crossproduct.z = v1.x * v2.y - v1.y * v2.x;
    return crossproduct;
}

int main()
{
    vector3d v1 = {0, 0, 0};
    vector3d v2 = {0, 0, 0};

    printf("Vector 1 - Enter value for x: ");
    scanf("%d", &v1.x);
    printf("Vector 1 - Enter value for y: ");
    scanf("%d", &v1.y);
    printf("Vector 1 - Enter value for z: ");
    scanf("%d", &v1.z);

    printf("Vector 2 - Enter value for x: ");
    scanf("%d", &v2.x);
    printf("Vector 2 - Enter value for y: ");
    scanf("%d", &v2.y);
    printf("Vector 2 - Enter value for z: ");
    scanf("%d", &v2.z);

    printf("Dotproduct: %d\n", dot_product(v1, v2));
    vector3d cp = cross_product(v1, v2);
    printf("Crossproduct: x:%d y:%d z:%d", cp.x, cp.y, cp.z);

    return 0;
}

//OUTPUT
Vector 1 - Enter value for x: 1
Vector 1 - Enter value for y: 2
Vector 1 - Enter value for z: 3
Vector 2 - Enter value for x: 3
Vector 2 - Enter value for y: 2
Vector 2 - Enter value for z: 1
Dotproduct: 10
Crossproduct: x:-4 y:-8 z:-4

以后这些小事自己想吧

Answer 2

您使用 typedef 创建结构的别名并在向量分析函数中使用该结构 (Passing struct to function). To access the fields of the struct use the . notation. There is another possiblitiy to pass structs to functions as a pointer to the struct, in this case you use the -> notation to access the fields (Passing pointers/references to structs into functions, https://www.tutorialspoint.com/cprogramming/c_structures.htm)

typedef struct 
{
    int x;
    int y;
    int z;
} vector3d;

int dot_product (vector3d v1, vector3d v2)
{
   return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
}

在此 link 中，使用的不是 3D 向量复数（大约为“2D 向量”），您可以对此进行调整：https://www.programiz.com/c-programming/c-structure-function

C 中使用结构的点积和叉积

Dot Product and Cross Product in C using structures

c

struct

vector

cross-product

dot-product