C语言习题（结构）

实际应用中经常会用到二维平面上的点，点的操作包括设置点的位置( pointT setPoint(double x , double y ) )，显示第n个点的位置( void showPoint(pointT *p，int n) )， 计算两个点的距离double distPoint(pointT pt1, pointT pt2)，并将点的坐标以及距离保存到文件Info.txt中void saveInfo (pointT pt1, pointT pt2, char *filename) 。试定义平面上点的数据类型pointT，并实现这些函数，自行编写main函数测试这些函数。

#include<stdio.h>
#include<math.h>

struct pointT{
    double x;
    double y;
};

struct pointT setPoint(double x, double y)
{
    struct pointT temp;
    
    temp.x = x;
    temp.y = y;
    return temp;
}

void showPoint(struct pointT *p, int n)
{
    printf("point%d(%.1f , %.1f)", n, (p+n-1)->x, (p+n-1)->y);
} 

double distPoint(struct pointT pt1, struct pointT pt2)
{
    return sqrt((pt1.x - pt2.x)*(pt1.x - pt2.x) + (pt1.y - pt2.y)*((pt1.y - pt2.y)));
}

void saveInfo(struct pointT pt1, struct pointT pt2, char *filename)
{
    //打开文件
    FILE *fp;
    fp = fopen(filename , "a");
    
    //操作
    fprintf(fp, "point1(%.1f , %.1f), point2(%.1f , %.1f)
", pt1.x, pt1.y, pt2.x, pt2.y);
    fprintf(fp, "dist between point1 and point2 is %.1f
", distPoint(pt1 , pt2));
    
    //关闭文件
    fclose(fp);
}

// test
int main()
{
    struct pointT pt[3];
    
    pt[0] = setPoint(0 , 0);
    pt[1] = setPoint(4 , 0);
    pt[2] = setPoint(4 , 3);
    
    showPoint(pt , 2);
    
    printf("dist between point1 and point2 is %.1f
", distPoint(pt[0] , pt[2]));
    
    char *filename = "Info.txt";
    saveInfo(pt[0], pt[2], filename);
    
    return 0;
}

 补充说明：

代码是按c89写的,这个标准里必须使用

struct pointT pt1

声明，而不能使用

pointT pt

如果必要,自行修改。

（本人用的编译器比较旧）