////////////////////////////
//三角形画板，可选三种颜色
//画完三角后点颜色可以换填充色
/////////////////////////////
#include<stdio.h>
#include<conio.h>
#include<graphics.h>

int main(void)

{
    initgraph(300,480);
    setbkcolor(WHITE);
    cleardevice();//设置背景
   
    //绘制选色区
    setfillcolor(RED);
    fillrectangle(0,450,100,480);
    setfillcolor(YELLOW);
    fillrectangle(100,450,200,480);
    setfillcolor(BLUE);
    fillrectangle(200,450,300,480);
   
    MOUSEMSG o;
       int color;
    char yanse;

    while(!kbhit())
    {
        while(!MouseHit())
        {
            if(true)
            {
                //点击鼠标选择颜色
                o=GetMouseMsg();
                if(o.uMsg==WM_LBUTTONDOWN)
                {
                    if((o.x>=0&&o.x<=100)&&(o.y>=450&&o.y<=480)) yanse='R';
                    else if((o.x>=100&&o.x<=200)&&(o.y>=450&&o.y<=480)) yanse='Y';
                    else if((o.x>=200&&o.x<=300)&&(o.y>=450&&o.y<=480)) yanse='B';
                    else 0;
                    
                    switch(yanse)
                    {
                    case'R': color=RED;  break;
                    case'Y': color=YELLOW;  break;
                    case'B': color=BLUE;  break;
                    default: 0;
                    }
                    setfillcolor(color);//
                }
            }
        }
        fillcircle(10,10,10);//当前颜色标示符

        //绘制三角形
        POINT p[3];
        int i;
        MOUSEMSG m;
        for(i=0;i<3;)
        {
            if(true)
                m=GetMouseMsg();
            if(m.uMsg==WM_LBUTTONDOWN)
            {
                p[i].x = m.x;
                p[i].y = m.y;
                i++;
            }
            
        }
        solidpolygon(p,3);        
    }
   
    return 0;
    getch();
    closegraph();
}

鼠标点好几次，隔好长时间才起作用

.