C++编程求直角坐标系中一点到直线的距离

Question

要求：（1）定义一个点类，有两个成员数据x和y；
（2）定义一个直线类，有三个成员数据a，b，c。分别表示直线方程ax+by+c=0的系数；
（3）在直线类中定义一个计算一点到直线距离的友元函数distance，其中点（x,y）到直线ax+by+c=0的距离计算公式为：d=fabs(a*x+b*y+c)/sqrt(a*a+b*b);
请C++高手帮帮忙咯！

Answer 1

#include "stdio.h"
#include "stdlib.h"
#include "string.h"

struct PCB {
char NAME[10]; /*进程名*/
int ROUND; /*进程轮转时间片*/
int REACHTIME; /*进程到达时间*/
int CPUTIME; /*进程占用CPU时间*/
int COUNT; /*计数器*/
int NEEDTIME; /*进程完成还要的CPU时间*/
char STATE; /*进程的状态*/
struct PCB *NEXT; /*链指针*/
};

struct LINK { /*PCB的链结构*/
struct PCB *RUN; /*当前运行进程指针*/
struct PCB *READY; /*就绪队列头指针*/
struct PCB *TAIL; /*就绪队列尾指针*/
struct PCB *FINISH; /*完成队列头指针*/
};

void INIT(LINK *); /*对PCB的链结构初始化*/
void INSERT(LINK *); /*将执行了一个单位时间片数且还未完成的进程的PCB插到就绪队列的队尾*/
void FIRSTIN(LINK *); /*将就绪队列中的第一个进程投入运行*/
void PRINT(LINK *); /*打印每执行一个时间片后的所有进程的状态*/
void PR(PCB *); /*打印一个进程的状态*/
int CREATE(LINK *,int); /*创建新的进程*/
void ROUNDSCH(LINK *); /*按时间片轮转法调度进程*/

void main() {
LINK pcbs;
int i;
INIT(&pcbs);
i=0;
printf("创建5个进程\n\n");
while(i<5) {
if(CREATE(&pcbs,i+1)==1) {
printf("进程已创建\n\n");
i++;
}
else
printf("进程创建失败\n\n");
}
FIRSTIN(&pcbs);
ROUNDSCH(&pcbs);
}

void ROUNDSCH(LINK *p) {
PCB *pcb;
while(p->RUN!=NULL) {
pcb=(PCB *)malloc(sizeof(PCB));
strcpy(pcb->NAME,p->RUN->NAME);
pcb->ROUND=p->RUN->ROUND;
pcb->REACHTIME=p->RUN->REACHTIME;
pcb->CPUTIME=p->RUN->CPUTIME;
pcb->COUNT=p->RUN->COUNT;
pcb->NEEDTIME=p->RUN->NEEDTIME;
pcb->STATE=p->RUN->STATE;
pcb->NEXT=p->RUN->NEXT;
pcb->CPUTIME++;
pcb->NEEDTIME--;
pcb->COUNT++;
if(pcb->NEEDTIME==0) {
pcb->NEXT=p->FINISH->NEXT;
p->FINISH->NEXT=pcb;
pcb->STATE='F';
p->RUN=NULL;
if(p->READY!=p->TAIL)
FIRSTIN(p);
}
else {
p->RUN=pcb;
if(pcb->COUNT==pcb->ROUND) {
pcb->COUNT=0;
if(p->READY!=p->TAIL) {
pcb->STATE='W';
INSERT(p);
FIRSTIN(p);
}
}
}
PRINT(p);
}
}

void INIT(LINK *p) {
p->RUN=NULL;
p->TAIL=p->READY=(PCB *)malloc(sizeof(PCB));
p->READY->NEXT=NULL;
p->FINISH=(PCB *)malloc(sizeof(PCB));
p->FINISH->NEXT=NULL;
}

int CREATE(LINK *p,int n) {
PCB *pcb,*q;
pcb=(PCB *)malloc(sizeof(PCB));
flushall();
printf("请输入第%d个进程的名称：\n",n);
gets(pcb->NAME);
printf("请输入第%d个进程的轮转时间片数：\n",n);
scanf("%d",&(pcb->ROUND));
printf("请输入第%d个进程的到达时间：\n",n);
scanf("%d",&(pcb->REACHTIME));
pcb->CPUTIME=0;
pcb->COUNT=0;
printf("请输入第%d个进程需运行的时间片数：\n",n);
scanf("%d",&(pcb->NEEDTIME));
pcb->STATE='W';
pcb->NEXT=NULL;
if(strcmp(pcb->NAME,"")==0||pcb->ROUND<=0||pcb->NEEDTIME<=0) /*输入错误*/
return 0;
q=p->READY;
while(q->NEXT!=NULL&&q->NEXT->REACHTIME<=pcb->REACHTIME)
q=q->NEXT;
pcb->NEXT=q->NEXT;
q->NEXT=pcb;
if(pcb->NEXT==NULL)
p->TAIL=pcb;
return 1;
}

void FIRSTIN(LINK *p) {
PCB *q;
q=p->READY->NEXT;
p->READY->NEXT=q->NEXT;
q->NEXT=NULL;
if(p->READY->NEXT==NULL)
p->TAIL=p->READY;
q->STATE='R';
p->RUN=q;
}

void INSERT(LINK *p) {
PCB *pcb;
pcb=(PCB *)malloc(sizeof(PCB));
strcpy(pcb->NAME,p->RUN->NAME);
pcb->ROUND=p->RUN->ROUND;
pcb->REACHTIME=p->RUN->REACHTIME;
pcb->CPUTIME=p->RUN->CPUTIME;
pcb->COUNT=p->RUN->COUNT;
pcb->NEEDTIME=p->RUN->NEEDTIME;
pcb->STATE=p->RUN->STATE;
pcb->NEXT=p->RUN->NEXT;
p->TAIL->NEXT=pcb;
p->TAIL=pcb;
p->RUN=NULL;
pcb->STATE='W';
}

void PRINT(LINK *p) {
PCB *pcb;
printf("执行一个时间片后的所有进程的状态：\n\n");
if(p->RUN!=NULL)
PR(p->RUN);
if(p->READY!=p->TAIL) {
pcb=p->READY->NEXT;
while(pcb!=NULL) {
PR(pcb);
pcb=pcb->NEXT;
}
}
pcb=p->FINISH->NEXT;
while(pcb!=NULL) {
PR(pcb);
pcb=pcb->NEXT;
}
}

void PR(PCB *p) {
printf("进程名：%s\n",p->NAME);
printf("进程轮转时间片：%d\n",p->ROUND);
printf("进程到达时间：%d\n",p->REACHTIME);
printf("进程占用CPU时间：%d\n",p->CPUTIME);
printf("计数器：%d\n",p->COUNT);
printf("进程完成还要的CPU时间：%d\n",p->NEEDTIME);
printf("进程的状态：%c\n\n",p->STATE);
}

Answer 2

#include "iostream.h"
#include "math.h"

class point
{
public:
float x;
float y;

//构造函数
point(float x,float y)
{
this->x=x;
this->y=y;
}
};

class line
{
float a;
float b;
float c;

public:
//构造函数
line(float a,float b,float c)
{
this->a=a;
this->b=b;
this->c=c;
}

float getDistance(point p)
{
float x,y;
x=p.x;
y=p.y;
return fabs(a*x+b*y+c)/sqrt(a*a+b*b);
}
};

void main()
{
float x,y;
cout<<"请输入点的X坐标:";
cin>>x;
cout<<"请输入点的Y坐标:";
cin>>y;
point p(x,y);

float a,b,c;
cout<<"请输入a:";
cin>>a;
cout<<"请输入b:";
cin>>b;
cout<<"请输入c:";
cin>>c;
line l(a,b,c);
cout<<"点到直线的距离为:"<<l.getDistance(p)<<endl;
}

Answer 3

#include<iostream>
#include<math.h>
using namespace std;

class point {
public:
float x,y;
point(float i,float j) {
x=i;
y=j;
}
};

class line;
float distance(const point &p, const line &l);

class line {
float a, b, c;
public:
friend float distance(const point &p, const line &l);
line(float _a, float _b, float _c) : a(_a), b(_b), c(_c) {}
};

int main()
{
point p1(2,4);
line l1(1,2,3);
cout<<"distance="<<distance(p1,l1)<<endl;
return 0;
}

float distance(const point &p, const line &l) {
return std::abs((l.a * p.x + l.b * p.y + l.c) /
std::sqrt(l.a * l.a + l.b * l.b));
}

Answer 4

具体方法如下：
#include "iostream.h"
#include "math.h"
class point
{
public:
float x;
float y;
//构造函数
point(float x,float y)
{
this->x=x;
this->y=y;
}
};
class line
{
float a;
float b;
float c;
public:
//构造函数
line(float a,float b,float c)
{
this->a=a;
this->b=b;
this->c=c;
}
float getDistance(point p)
{
float x,y;
x=p.x;
y=p.y;
return fabs(a*x+b*y+c)/sqrt(a*a+b*b);
}
};
void main()
{
float x,y;
coutx;
couty;
point p(x,y);

float a,b,c;
couta;
coutb;
coutc;
line l(a,b,c);
cout