Analog Clock source code using c++ and winBGI graphics

The is the sample example of a WinBGIm graphics library implementation. The program will create an Analog clock using WinBGIm library. WinBGIm library does not come by default in Codeblocks IDE. You have to setup WinBGIm library before using the below code. If you haven't done it yet then please follow my earlier article How to Setup WinBGIm graphics in Codeblocks.

If you encounter any errors please leave comments.

#include <graphics.h>
#include <winbgim.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <dos.h>
#include <string.h>
#include <iostream>
#include <ctime>

#define S_N_L (radius-10)        // Second Needle Length
#define S_N_C RED                   // Second needle Color
#define M_N_L (radius-20)           // Minute Needle Length
#define M_N_C LIGHTRED              // Minute Needle Color
#define H_N_L (radius-(radius/2))       // Hour Needle Length
#define H_N_C CYAN                     // Hour Needle Color

float cx,cy;
float radius=100;

void draw_face(float radius);
void get_time(int &h,int &m,int &s);
void second_needle(int s);
void minute_needle(int m,int s);
void hour_needle(int h,int m,int s);

int main(void)
{
    /* request auto detection */
    int gdriver = DETECT, gmode, errorcode;
    initgraph(&gdriver,&gmode,"");
    /***********************************/
    cx=getmaxx()/2.0; // cx is center x value.
    cy=getmaxy()/2.0; // cy is center y value.
    /** Now the point (cx,cy) is the center of your screen. **/

    float x,y;
    int hour,minute,second;
    draw_face(radius);
    while(!kbhit())
    {
        get_time(hour,minute,second);
        second_needle(second);
        minute_needle(minute,second);
        hour_needle(hour,minute,second);
        circle(cx,cy,2);
        delay(100);
    }
    getch();
    closegraph();
    return 0;
}
//*************** FUNCTIONS DEFINITIONS *****************//

void draw_face(float radius)
{
    int theta=0; // theta is the angle variable.
    float x,y;
    /** Draw Clock Border. **/
    circle(cx,cy,radius+24);
    circle(cx,cy,radius+23);
    /** Draw GREEN material border. **/
    setcolor(BROWN);    // I like a wooden frame!
    /** Paint the border. **/
    for(int i=0;i<9;i++)
    circle(cx,cy,radius+13+i);
    /** Set the color white. **/
    setcolor(WHITE);
    /** Draw outer-inner border. **/
    circle(cx,cy,radius+12);
    circle(cx,cy,radius+10);
    /** Draw center dot. **/
    circle(cx,cy,2);
    int i=0;
    /** DRAW NUMERIC POINTS **/
    do{
        /** Getting (x,y) for numeric points **/
        x=cx+radius*cos(theta*M_PI/180);
        y=cy+radius*sin(theta*M_PI/180);
        /** Draw Numeric Points **/
        circle(x,y,2);
        /* Draw Dots around each numeric points **/
        circle(x+5,y,0);
        circle(x-5,y,0);
        circle(x,y+5,0);
        circle(x,y-5,0);
        /** Increase angle by 30 degrees, 
        which is the circular distance between each numeric points. **/
        theta+=30;
        /** Increase i by 1. **/
        i++;

    } while(i!=12); //LIMIT NUMERIC POINTS UPTO =12= Numbers.
    i=0;
    /** DRAW DOTS BETWEEN NUMERIC POINTS. **/
    do{
        putpixel(cx+radius*cos(i*M_PI/180)
        ,cy+radius*sin(i*M_PI/180),DARKGRAY);
        i+=6;
    }while(i!=360);

    /** FACE COMPLETELY DRAWN. **/
}
//================
/** Function to get the current time. **/
void get_time(int &h,int &m,int &s)
{
    time_t rawtime;
    struct tm *t;
    time(&rawtime);
    t = gmtime(&rawtime);
    h=t->tm_hour;
    m=t->tm_min;
    s=t->tm_sec;
}
//=================
/** Function to draw Second needle. **/
void second_needle(int s)
{
    float angle=-90;
    float sx,sy;
    setcolor(0);
    sx=cx+S_N_L*cos((angle+s*6-6)*M_PI/180);
    sy=cy+S_N_L*sin((angle+s*6-6)*M_PI/180);
    line(cx,cy,sx,sy);
    setcolor(S_N_C);
    sx=cx+S_N_L*cos((angle+s*6)*M_PI/180);
    sy=cy+S_N_L*sin((angle+s*6)*M_PI/180);
    line(cx,cy,sx,sy);
}
/** Function to draw Minute needle. **/
void minute_needle(int m,int s)
{
    float angle=-90;
    float sx,sy;
    setcolor(0);
    sx=cx+M_N_L*cos((angle+m*6-6)*M_PI/180);
    sy=cy+M_N_L*sin((angle+m*6-6)*M_PI/180);
    line(cx,cy,sx,sy);
    setcolor(M_N_C);
    sx=cx+M_N_L*cos((angle+m*6/*+(s*6/60)*/)*M_PI/180);
    sy=cy+M_N_L*sin((angle+m*6/*+(s*6/60)*/)*M_PI/180);
    line(cx,cy,sx,sy);
}
/** Function to draw Hour needle. **/
void hour_needle(int h,int m,int s)
{
    float angle=-90;
    float sx,sy;
    setcolor(0);
    sx=cx+H_N_L*cos((angle+h*30-(m*30/60))*M_PI/180);
    sy=cy+H_N_L*sin((angle+h*30-(m*30/60))*M_PI/180);
    line(cx,cy,sx,sy);
    setcolor(H_N_C);
    sx=cx+H_N_L*cos((angle+h*30+(m*30/60))*M_PI/180);
    sy=cy+H_N_L*sin((angle+h*30+(m*30/60))*M_PI/180);
    line(cx,cy,sx,sy);
}