A C code to visualize launching of a rocket in MSDOS

/*
 C code to display the simple motion of a rocket
 Sandipan Dey
 BCSE, JU, Kolkata
 2002
*/

#include <stdio.h>
#include <conio.h>
#include <graphics.h>
#include <stdlib.h>
#include <string.h>
#include <dos.h>
#define INPUTFILE "rocket.bmp" // a rocket image
#define MAX 256
#define MAXF 500

void Name() {

    rectangle(515,335,630,465);
    outtextxy(520,340,"SANDIPAN DEY");
    outtextxy(520,350,"BCSE-IV");
    outtextxy(520,360,"Roll-99710");
    line(515,370,630,370);
    outtextxy(520,375,"Press Keys:");
    line(515,388,630,388);
    outtextxy(520,395,"'->'-Speed Up");
    outtextxy(520,410,"'<-'- ,, Down");
    outtextxy(520,425,"'S'-Sound On");
    outtextxy(520,439,"'M'-Sound Off");
    outtextxy(520,455,"'X'-Exit");
}

void TwinkleStar(int c) {

    int x=random(300),y=random(480),c1=getmaxcolor();
    putpixel(x-1,y-1,c1);
    putpixel(x-1,y,c1);
    putpixel(x,y,c1);
    putpixel(x,y-1,c1);
    x=random(400)+300;y=random(480);
    putpixel(x-1,y-1,c1);
    putpixel(x-1,y,c1);
    putpixel(x,y,c1);
    putpixel(x,y-1,c1);
    for(int i=0;i<300;++i) {
        x=random(300);y=random(480);
        putpixel(x,y,c);
        putpixel(x+1,y+1,c);
        putpixel(x,y+1,c);
    }
    for(i=0;i<300;++i)  {
        x=random(400)+300;y=random(480);
        putpixel(x,y,c);
        putpixel(x+1,y,c);
        putpixel(x+1,y+1,c);
    }
}

void Meteor(int c) {

    int x=random(320),y=random(480);
    for(int i=x,j=y;i>=0;--i,--j) {
        putpixel(i,j,getmaxcolor());
        putpixel(i-1,j-1,getmaxcolor());
        putpixel(i,j-1,getmaxcolor());
        putpixel(i-1,j,getmaxcolor());
        /////////////////////
        delay(1);
        putpixel(i+1,j+1,c);
        putpixel(i,j,c);
        putpixel(i+1,j,c);
        putpixel(i,j+1,c);
    }
}

void main(int argc,char* argv[]) {

    FILE* fp=NULL,*fo=NULL;
    void* bmp;
    int freq=0;
    if((fp=fopen(INPUTFILE,"rb"))==NULL)
    {printf("\n File Not Found!");fclose(fp);getch();exit(0);}    // File Not Found
    long int imgoffset;
    if(fgetc(fp)!='B' || fgetc(fp)!='M') {      // Check Signature

        printf("\n Not a valid BMP File!!!");
        fclose(fp);
        fclose(fo);
        getch();
        exit(0);
    }
    fseek(fp,10,0);         // Find Offset of Data
    imgoffset=fgetc(fp)+(fgetc(fp)<<8)+(fgetc(fp)<<16)+(fgetc(fp)<<24);  // Data Offset
    long int w,h;
    fseek(fp,18,0);
    w=fgetc(fp)+(fgetc(fp)<<8)+(fgetc(fp)<<16)+(fgetc(fp)<<24);
    h=fgetc(fp)+(fgetc(fp)<<8)+(fgetc(fp)<<16)+(fgetc(fp)<<24);
    int gd=VGA,gm=VGAHI,x=0,y=h,c;
    struct palettetype pal;
    //int gd=DETECT,gm,x=0,y=h,c;
    initgraph(&gd,&gm,"");
    getpalette(&pal);
    for (int i=0; i<16; i++)
        setrgbpalette(pal.colors[i],i*2,i*3,i*4);
    fseek(fp,imgoffset,0);
    while(!feof(fp)) {
        c=fgetc(fp);
        putpixel(x,y,c/16);
        x=(x+1)%w;
        if(!x){--y;}
    }
    fclose(fp);
    c=getpixel(64,86);
    Name();
    outtextxy(25,25,"PRESS ANY KEY TO START");
    getch();
    setcolor(c);
    outtextxy(25,25,"PRESS ANY KEY TO START");
    setcolor(getmaxcolor());
    int size=imagesize(300,315,330,439);
    bmp=malloc(size);
    getimage(300,315,330,439,bmp);
    x=300;y=315;
    setfillstyle(SOLID_FILL,c);
    int c1,c2,d=10,flag=0;
    randomize();
    do {
        if(c1==0 && c2==75){d+=10;if(freq<MAXF)++freq;}
        else if(c1==0 && c2==77){d-=10;if(freq>10)--freq;}
        if(d>=500)d=500;
        else if(d<=1)d=1;
        while(!kbhit()) {
            putimage(x,y,bmp,COPY_PUT);
            delay(d);
            y-=1;
            if(y<=-10) {
                y=350;bar(300,0,330,480);
            }
            TwinkleStar(c);
            //if(!(y%100))Meteor(c);
            if(flag) {
                if(freq<MAXF){
                    ++freq;sound(freq);
                }
            }
            Name();
        }
        if ((c1=getch())==0){
            c2=getch();
        }
        else if(c1=='s' || c1=='S')flag=1;
        else if(c1=='m' || c1=='M'){
            flag=0;nosound();freq=0;
        }
        //fflush(stdin);
    }
    while(c1!='x' && c1!='X');
    closegraph();
    free(bmp);
    nosound();
}