#include<stdio.h>

#include"graphics.h"

#include<math.h>

#include<stdlib.h>

void DDALine(int x0, int y0, int x1, int y1);

int main()

{

    int gdriver = DETECT, gmode;

    int x0, y0, x1, y1;

    printf("please input the start point:\n");

    scanf_s("%d%d", &x0, &y0);

    printf("please input the end point:\n");

    scanf_s("%d%d", &x1, &y1);

    initgraph(&gdriver, &gmode, "");    //初始化图形界面

    DDALine(x0, y0, x1, y1);

    system("pause");    //暂停函数

    closegraph();   //关闭图形界面

}

void DDALine(int x0, int y0, int x1, int y1)

{

    int dx=x1-x0, dy=y1-y0,k;

    double x = x0, y = y0, xIncre, yIncre, espl;

    espl = abs(dy);

    if (abs(dx) > abs(dy))

        espl = abs(dx);

    xIncre = 1.0*dx / espl;

    yIncre = 1.0*dy / espl;

    for (k = 0; k < espl;k++)

    {

        putpixel((int)x, (int)y, RED);

        x += xIncre;

        y += yIncre;

    }

}

DDA画线算法